in one embodiment the dyes of the invention serve as probes for continuous monitoring of renal function , especially for critically ill patients and kidney transplant patients . in another embodiment , the dyes of the invention are useful for dynamic hepatic function monitoring , especially for critically ill patients and liver transplant patients . in another embodiment , the dyes of the invention are useful for real - time determination of cardiac function , especially in patients with cardiac diseases . in another embodiment , the dyes of the invention are useful for monitoring organ perfusion , especially for critically ill , cancer , and organ transplant patients . in another embodiment , the dyes are useful for assessing the functional status of tumors and for monitoring tumor perfusion , such as in renal or hepatic cancer patients . the novel dyes of the present invention are prepared according to the methods well known in the art , as illustrated in general in fig1 - 7 and described for specific compounds in examples 1 - 11 . in one embodiment , the novel compounds , also called tracers , of the present invention have the formula 1 , wherein r 3 , r 4 , r 5 , r 6 and r 7 , and y 1 are independently selected from the group consisting of — h , c1 - c5 alkoxyl , c1 - c5 polyalkoxyalkyl , c1 - c10 polyhydroxyalkyl , c5 - c20 polyhydroxyaryl , mono - and disaccharides , nitro , hydrophilic peptides , arylpolysulfonates , c1 - c5 alkyl , c1 - c10 aryl , — so 3 t , — co 2 t , — oh , —( ch 2 ) a so 3 t , —( ch 2 ) a oso 3 t , —( ch 2 ) a nhso 3 t , —( ch 2 ) a co 2 ( ch 2 ) b so 3 t , —( ch 2 ) a oco ( ch 2 ) b so 3 t , — ch 2 ( ch 2 — o — ch 2 ) c — ch 2 — oh , —( ch 2 ) d — co 2 t , — ch 2 —( ch 2 — o — ch 2 ) e — ch 2 — co 2 t , —( ch 2 ) f — nh 2 , — ch 2 —( ch 2 — o — ch 2 ) g — ch 2 — nh 2 , —( ch 2 ) h — n ( r a )—( ch 2 ) i — co 2 t , and —( ch 2 ) j — n ( r b )— ch 2 —( ch 2 — o — ch 2 ) k — ch 2 — co 2 t ; w 1 is selected from the group consisting of — cr c r d , — o —, — nr c , — s —, and — se ; a , b , d , f , h , i , and j independently vary from 1 - 5 ; c , e , g , and k independently vary from 1 - 20 ; r a , r b , r c , and r d are defined in the same manner as y 1 ; t is a negative charge . in another embodiment , the novel compounds of the present invention have the general formula 2 , wherein r 8 , r 9 , r 10 , r 11 , r 12 , r 13 , r 14 , and y 2 are independently selected from the group consisting of — h , c1 - c5 alkoxyl , c1 - c5 polyalkoxyalkyl , c1 - c10 polyhydroxyalkyl , c5 - c20 polyhydroxyaryl , mono - and disaccharides , nitro , hydrophilic peptides , arylpolysulfonates , c1 - c5 alkyl , c1 - c10 aryl , — so 3 t , — co 2 t , — oh , —( ch 2 ) a so 3 t , —( ch 2 ) a oso 3 t , —( ch 2 ) a nhso 3 t , —( ch 2 ) a co 2 ( ch 2 ) b so 3 t , —( ch 2 ) a oco ( ch 2 ) b so 3 t , — ch 2 ( ch 2 — o — ch 2 ) c — ch 2 — oh , —( ch 2 ) d — co 2 t , — ch 2 —( ch 2 — o — ch 2 ) e — ch 2 — co 2 t , —( ch 2 ) f — nh 2 , — ch 2 —( ch 2 — o — ch 2 ) g — ch 2 — nh 2 , —( ch 2 ) h — n ( r a )—( ch 2 ) i — co 2 t , and —( ch 2 ) j — n ( r b )— ch 2 —( ch 2 — o — ch 2 ) k — ch 2 — co 2 t ; w 2 is selected from the group consisting of — cr c r d , — o —, — nr c , — s —, and — se ; a , b , d , f , h , i , and j independently vary from 1 - 5 ; c , e , g , and k independently vary from 1 - 20 ; r a , r b , r c , and r d are defined in the same manner as y 2 ; t is a negative charge . in another embodiment , the novel compositions of the present invention have the general formula 3 , wherein r 15 , r 16 , r 17 , r 18 , r 19 , r 20 , r 21 , r 22 , r 23 , y 3 , and z 3 are independently selected from the group consisting of — h , c1 - c5 alkoxyl , c1 - c5 polyalkoxyalkyl , c1 - c10 polyhydroxyalkyl , c5 - c20 polyhydroxyaryl , mono - and disaccharides , nitro , hydrophilic peptides , arylpolysulfonates , c1 - c5 alkyl , c1 - c10 aryl , — so 3 t , — co 2 t , — oh , —( ch 2 ) a so 3 t , —( ch 2 ) a oso 3 t , —( ch 2 ) a nhso 3 t , —( ch 2 ) a co 2 ( ch 2 ) b so 3 t , —( ch 2 ) a oco ( ch 2 ) b so 3 t , — ch 2 ( ch 2 — o — ch 2 ) c — ch 2 — oh , —( ch 2 ) d — co 2 t , — ch 2 —( ch 2 — o — ch 2 ) e — ch 2 — co 2 t , —( ch 2 ) f — nh 2 , — ch 2 —( ch 2 — o — ch 2 ) g — ch 2 — nh 2 , —( ch 2 ) h — n ( r a )—( ch 2 ) i — co 2 t , and —( ch 2 ) j — n ( r b )— ch 2 —( ch 2 — o — ch 2 ) k — ch 2 — co 2 t ; w 3 and x 3 are selected from the group consisting of — cr c r d , — o —, — nr c , — s —, and — se ; v 3 is a single bond or is selected from the group consisting of — o —, — s —, — se —, and — nr a ; a , b , d , f , h , i , and j independently vary from 1 - 5 ; c , e , g , and k independently vary from 1 - 50 ; a 3 and b 3 vary from 0 to 5 ; r a , r b , r c , and r d are defined in the same manner as y 3 ; t is either h or a negative charge . in another embodiment , the novel compounds of the present invention have the general formula 4 , wherein r 24 , r 25 , r 26 , r 27 , r 28 , r 29 , r 30 , r 31 , r 32 , r 33 , r 34 , r 35 , r 36 , y 4 , and z 4 are independently selected from the group consisting of — h , c1 - c5 alkoxyl , c1 - c5 polyalkoxyalkyl , c1 - c10 polyhydroxyalkyl , c5 - c20 polyhydroxyaryl , mono - and disaccharides , nitro , hydrophilic peptides , arylpolysulfonates , c1 - c5 alkyl , c1 - c10 aryl , — so 3 t , — co 2 t , — oh , —( ch 2 ) a so 3 t , —( ch 2 ) a oso 3 t , —( ch 2 ) a nhso 3 t , —( ch 2 ) a co 2 ( ch 2 ) b so 3 t , —( ch 2 ) a oco ( ch 2 ) b so 3 t , — ch 2 ( ch 2 — o — ch 2 ) c — ch 2 — oh , —( ch 2 ) d — co 2 t , — ch 2 —( ch 2 — o — ch 2 ) e — ch 2 — co 2 t , —( ch 2 ) f — nh 2 , — ch 2 —( ch 2 — o — ch 2 ) g — ch 2 — nh 2 , —( ch 2 ) h — n ( r a )—( ch 2 ) i — co 2 t , and —( ch 2 ) j — n ( r b )— ch 2 —( ch 2 — o — ch 2 ) k — ch 2 — co 2 t ; w 4 and x 4 are selected from the group consisting of — cr c r d , — o —, — nr c , — s —, and — se ; v 4 is a single bond or is selected from the group consisting of — o —, — s —, — se —, and — nr a ; a 4 and b 4 vary from 0 to 5 ; a , b , d , f , h , i , and j independently vary from 1 - 5 ; c , e , g , and k independently vary from 1 - 50 ; r a , r b , r c , and r d are defined in the same manner as y 4 ; t is either h or a negative charge . in another embodiment , the novel compounds of the present invention have the general formula 5 , wherein r 37 , r 38 , r 39 , r 40 , r 41 , r 42 , r 43 , r 44 , r 45 , y 5 , and z 5 are independently selected from the group consisting of — h , c1 - c5 alkoxyl , c1 - c5 polyalkoxyalkyl , c1 - c 10 polyhydroxyalkyl , c5 - c20 polyhydroxyaryl , mono - and disaccharides , nitro , hydrophilic peptides , arylpolysulfonates , c1 - c5 alkyl , c1 - c10 aryl , — so 3 t , — co 2 t , — oh , —( ch 2 ) a so 3 t , —( ch 2 ) a oso 3 t , —( ch 2 ) a nhso 3 t , —( ch 2 ) a co 2 ( ch 2 ) b so 3 t , —( ch 2 ) a oco ( ch 2 ) b so 3 t , — ch 2 ( ch 2 — o — ch 2 ) c — ch 2 — oh , —( ch 2 ) d — co 2 t , — ch 2 —( ch 2 — o — ch 2 ) e — ch 2 — co 2 t , —( ch 2 ) f — nh 2 , — ch 2 —( ch 2 — o — ch 2 ) g — ch 2 — nh 2 , —( ch 2 ) h — n ( r a )—( ch 2 ) i — co 2 t , and —( ch 2 ) j — n ( r b )— ch 2 —( ch 2 — o — ch 2 ) k — ch 2 — co 2 t ; w 5 and x 5 are selected from the group consisting of — cr c r d , — o —, — nr c , — s —, and — se ; v 5 is a single bond or is selected from the group consisting of — o —, — s —, — se —, and — nr a d 5 is a single or a double bond ; a 5 , b 5 and e 5 may be the same or different and are selected from the group consisting of — o —, — s —, — nr a , — cr c r d , cr c , and alkyl ; a 5 , b 5 , d 5 , and e 5 may together form a 6 or 7 membered carbocyclic ring or a 6 or 7 membered heterocyclic ring optionally containing one or more oxygen , nitrogen , or sulfur atom ; a , b , d , f , h , i , and j independently vary from 1 - 5 ; c , e , g , and k independently vary from 1 - 50 ; a 5 and b 5 vary from 0 to 5 ; r a , r b , r c , and r d are defined in the same manner as y 5 ; t is either h or a negative charge . in another embodiment , the novel compounds of the present invention have the general formula 6 , wherein r 46 , r 47 , r 48 , r 49 , r 50 , r 51 , r 52 , r 53 , r 54 , r 55 , r 56 , r 57 , r 58 , y 6 , and z 6 are independently selected from the group consisting of — h , c1 - c5 alkoxyl , c1 - c5 polyalkoxyalkyl , c1 - c10 polyhydroxyalkyl , c5 - c20 polyhydroxyaryl , mono - and disaccharides , nitro , hydrophilic peptides , arylpolysulfonates , c1 - c5 alkyl , c1 - c10 aryl , — so 3 t , — co 2 t , — oh , —( ch 2 ) a so 3 t , —( ch 2 ) a oso 3 t , —( ch 2 ) a nhso 3 t , —( ch 2 ) a co 2 ( ch 2 ) b so 3 t , —( ch 2 ) a oco ( ch 2 ) b so 3 t , — ch 2 ( ch 2 — o — ch 2 ) c — ch 2 — oh , —( ch 2 ) d — co 2 t , — ch 2 —( ch 2 — o — ch 2 ) e — ch 2 — co 2 t , —( ch 2 ) f — nh 2 , — ch 2 —( ch 2 — o — ch 2 ) g — ch 2 — nh 2 , —( ch 2 ) h — n ( r a )—( ch 2 ) i — co 2 t , and —( ch 2 ) j — n ( r b )— ch 2 —( ch 2 — o — ch 2 ) k — ch 2 — co 2 t ; w 6 and x 6 are selected from the group consisting of — cr c r d , — o —, — nr c , — s —, and — se ; v 6 is a single bond or is selected from the group consisting of — o —, — s —, — se —, and — nr a ; d 6 is a single or a double bond ; a 6 , b 6 and e 6 may be the same or different and are selected from the group consisting of — o —, — s —, — nr a , — cr c r d , cr c , and alkyl ; a 6 , b 6 , d 6 , and e 6 may together form a 6 or 7 membered carbocyclic ring or a 6 or 7 membered heterocyclic ring optionally containing one or more oxygen , nitrogen , or sulfur atom ; a , b , d , f , h , i , and j independently vary from 1 - 5 ; c , e , g , and k independently vary from 1 - 50 ; a 5 and b 5 vary from 0 to 5 ; r a , r b , r c , and r d are defined in the same manner as y 6 ; t is either h or a negative charge . the compounds of the invention can be formulated into diagnostic and therapeutic compositions for enteral or parenteral administration . these compositions contain an effective amount of the dye along with conventional pharmaceutical carriers and excipients appropriate for the type of administration contemplated . for example , parenteral formulations advantageously contain the inventive agent in a sterile aqueous solution or suspension . parenteral compositions may be injected directly or mixed with a large volume parenteral composition for systemic administration . such solutions also may contain pharmaceutically acceptable buffers and , optionally , electrolytes such as sodium chloride . formulations for enteral administration may vary widely , as is well known in the art . in general , such formulations are liquids , which include an effective amount of the inventive agent in aqueous solution or suspension . such enteral compositions may optionally include buffers , surfactants , thixotropic agents , and the like . compositions for oral administration may also contain flavoring agents and other ingredients for enhancing their organoleptic qualities . the compositions are administered in doses effective to achieve the desired effect or result . the dosage of the tracers may vary according to the clinical procedure contemplated and generally ranges from 1 picomolar to 100 millimolar . the compositions may be administered to a patient , typically a warm - blooded animal either systemically or locally to the organ or tissue to be imaged , and the patient then subject to the imaging procedure . the tracers may be administered to the patient by any suitable method , including intravenous , intraperitoneal , or subcutaneous injection or infusion , oral administration , transdermal absorption through the skin , aerosols , or by inhalation . the detection of the tracers is achieved by optical fluorescence , absorbance , or light scattering methods known in the art ( muller et al . eds ., medical optical tomography , spie volume is11 , 1993 , which is expressly incorporated herein by reference ) using invasive or non - invasive probes such as endoscopes , catheters , ear clips , hand bands , surface coils , finger probes , and the like . physiological function is correlated with the clearance profiles and rates of these agents from body fluids ( dorshow et al ., non - invasive fluorescence detection of hepatic and renal function , bull . am . phys . soc . 1997 , 42 , 681 , which is expressly incorporated by reference herein ). the inventive composition may be administered for imaging by more than one modality . as one example , the composition may be used for imaging by optical imaging alone , by nuclear imaging alone , or by both optical and nuclear imaging modalities when a radioactive isotope is included in the chemical formula , such as replacing a halogen atom with a radioactive halogen , and / or including a radioactive metal ion such as tc 99 , in 111 , etc . as another example , the composition may be used for imaging by optical imaging alone , by magnetic resonance ( mr ) alone , or by both optical and mr modalities when a paramagnetic metal ion such as gadolinium or manganese is included in the chemical formula . it will also be appreciated that the inventive compositions may be administered with other contrast agents or media used to enhance an image from a non - optical modality . these include agents for enhancing an image obtained by modalities including but not limited to mr , ultrasound ( us ), x - ray , positron emission tomography ( pet ), computed tomography ( ct ), single photon emission computed tomography ( spect ), optoacoustic ( e . g . u . s . pat . nos . 5 , 840 , 023 and 5 , 977 , 538 which are expressly incorporated by reference herein in their entirety ), etc . both optical and non - optical agents may be formulated as a single composition ( that is , one composition containing one , two , or more components , for example , an optical agent and a mr agent ), or may be formulated as separate compositions . the inventive optical imaging contrast agent and the non - optical contrast agent are administered in doses effective to achieve the desired enhancement , diagnosis , therapy , etc ., as known to one skilled in the art . the inventive compositions , either alone or combined with a contrast agent , may be administered to a patient , typically a warm - blooded animal , systemically or locally to the organ or tissue to be imaged . the patient is then imaged by optical imaging and / or by another modality . as one example of this embodiment , the inventive compounds may be added to contrast media compositions . as another example , the inventive compositions may be co - administered with contrast media , either simultaneously or within the same diagnostic and / or therapeutic procedure ( for example , administering the inventive composition and administering a contrast agent then performing optical imaging followed by another imaging modality , or administering the inventive composition and administering a contrast agent then performing another imaging modality followed by optical imaging , or administering the inventive composition and optical imaging , then administering a contrast agent and mr , us , ct , etc . imaging , or administering a contrast agent and imaging by mr , us , ct , etc ., then administering the inventive composition and optical imaging , or administering the inventive composition and a contrast agent , and simultaneously imaging by an optical modality and mr , us , ct , etc .). as another example , an optical imaging agent may be added as an additive or excipient for a non - optical imaging modality . in this embodiment , the optically active component , such as the dyes disclosed herein , could be added as a buffering agent to control ph or as a chelate to improve formulation stability , etc . in mr contrast media , ct contrast media , x - ray contrast media , us contrast media , etc . the mr , ct , x - ray , us contrast media would then also function as an optical imaging agent . the information obtained from the modality using the non - optical contrast agent is useful in combination with the image obtained using the optical contrast agent . in one embodiment , the agents may be formulated as micelles , liposomes , microcapsules , or other microparticles . these formulations may enhance delivery , and localization of the inventive compounds to / at the desired organ or site . the target specificity of these formulations can be enhanced by using suitable targeting molecules such as peptides , saccharides , fatty acids , etc . preparation and loading of these are well known in the art . as one example , liposomes may be prepared from dipalmitoyl phosphatidylcholine ( dppc ) or egg phosphatidylcholine ( pc ) because this lipid has a low heat transition . liposomes are made using standard procedures as known to one skilled in the art ( e . g ., braun - falco et al ., ( eds . ), griesbach conference , liposome dermatics , springer - verlag , berlin ( 1992 )). polycaprolactone , poly ( glycolic ) acid , poly ( lactic ) acid , polyanhydride or lipids may be formulated as microspheres . as an illustrative example , the optical agent may be mixed with polyvinyl alcohol ( pva ), the mixture then dried and coated with ethylene vinyl acetate , then cooled again with pva . in a liposome , the optical agent may be within one or both lipid bilayers , in the aqueous between the bilayers , or with the center or core . liposomes may be modified with other molecules and lipids to form a cationic liposome . liposomes may also be modified with lipids to render their surface more hydrophilic which increases their circulation time in the bloodstream . the thus - modified liposome has been termed a “ stealth ” liposome , or a long - lived liposome , as described in u . s . pat . nos . 6 , 277403 ; 6 , 610 , 322 ; 5 , 631 , 018 ; 5 , 395 , 619 ; and 6 , 258 , 378 , each of which is expressly incorporated by reference herein in its entirety , and in stealth liposomes , lasic and martin ( eds .) 1995 , crc press , london . encapsulation methods include detergent dialysis , freeze drying , film forming , injection , as known to one skilled in the art and disclosed in , for example , u . s . pat . no . 6 , 406 , 713 which is expressly incorporated by reference herein in its entirety . the agent formulated in liposomes , microcapsules , etc . may be administered by any of the routes previously described . in a formulation applied topically , the optical agent is slowly released over time . in an injectable formulation , the liposome capsule circulates in the bloodstream and is delivered to a desired site . as another example , microparticles such as ultra small iron oxide particles ( uspio ) and other metallic particles such as silver or gold particles coated with or attached ( covalently or non - covalently ) with the inventive compounds may be used for optical imaging and / or mri . such particles are known to one skilled in the art as disclosed in , for example , u . s . pat . no . 5 , 492 , 814 and journal of biomedical optics 8 ( 3 ), 472 - 478 ( july 2003 ) which are expressly incorporated by reference herein in their entirety . organ function can be assessed either by the differences in the manner in which the normal and impaired cells remove the tracer from the bloodstream , by measuring the rate or accumulation of these tracers in the organs or tissues , or by obtaining tomographic images of the organs or tissues . blood pool clearance may be measured non - invasively from convenient surface capillaries such as those found in an ear lobe or a finger , for example , using an ear clip or finger clip sensor , or may be measured invasively using an endovascular catheter . accumulation of the tracer within the cells of interest can be assessed in a similar fashion . the clearance of the tracer dyes may be determined by selecting excitation wavelengths and filters for the emitted photons . the concentration - time curves may be analyzed in real time by a microprocessor . in order to demonstrate feasibility of the inventive compounds to monitor organ function , a non - invasive absorbance or fluorescence detection system to monitor the signal emanating from the vasculature infused with the compounds is used . indole derivatives , such as those of formulas 1 - 6 , fluoresce at a wavelength between 350 nm and 1300 nm when excited at the appropriate wavelength as is known to , or readily determined by , one skilled in the art . in addition to the noninvasive techniques , a modified pulmonary artery catheter can be used to make the necessary measurements ( dorshow et al ., monitoring physiological function by detection of exogenous fluorescent contrast agents , in optical diagnostics of biological fluids iv , priezzhev and asakura , editors , procedings of spie 1999 , 3599 , 2 - 8 , which is expressly incorporated by reference herein ). currently , pulmonary artery catheters measure only intravascular pressures , cardiac output and other derived measures of blood flow . critically ill patients are managed using these parameters , but rely on intermittent blood sampling and testing for assessment of renal function . these laboratory parameters represent discontinuous data and are frequently misleading in many patient populations . yet , importantly , they are relied upon heavily for patient assessment , treatment decisions , and drug dosing . the modified pulmonary artery catheter incorporates an optical sensor into the tip of a standard pulmonary artery catheter . this wavelength specific optical sensor can monitor the renal function specific elimination of an optically detectable chemical entity . thus , by a method analogous to a dye dilution curve , real - time renal function can be monitored by the disappearance of the optically detected compound . modification of a standard pulmonary artery catheter only requires making the fiber optic sensor wavelength specific , as is known to one skilled in this art . catheters that incorporate fiber optic technology for measuring mixed venous oxygen saturation currently exist . the present invention may be used for rapid bedside evaluation of renal function and also to monitor the efficiency of hemodialysis . the invention is further demonstrated by the following examples . since many modifications , variations , and changes in detail may be made to the described embodiments , it is intended that all matter in the foregoing description and shown in the accompanying drawings be interpreted as illustrative and not limiting . fig1 , compound 5 , y 7 ═ so 3 − ; x 7 ═ h ; n = 1 a mixture of 3 - methyl - 2 - butanone ( 25 . 2 ml ), and p - hydrazinobenzenesulfonic acid ( 15 g ) in acetic acid ( 45 ml ) was heated at 110 ° c . for 3 hours . after reaction , the mixture was allowed to cool to room temperature and ethyl acetate ( 100 ml ) was added to precipitate the product , which was filtered and washed with ethyl acetate ( 100 ml ). the intermediate compound , 2 , 3 , 3 - trimethylindolenium - 5 - sulfonate ( fig1 , compound 3 ) was obtained as a pink powder in 80 % yield . a portion of compound 3 ( 9 . 2 g ) in methanol ( 115 ml ) was carefully added to a solution of koh in isopropanol ( 100 ml ). a yellow potassium salt of the sulfonate was obtained in 85 % yield after vacuum - drying for 12 hours . a portion of the 2 , 3 , 3 - trimethylindolenium - 5 - sulfonate potassium salt ( 4 g ) and 1 , 3 - propanesultone ( 2 . 1 g ) was heated in dichlorobenzene ( 40 ml ) at 110 ° c . for 12 hours . the mixture was allowed to cool to room temperature and the resulting precipitate was filtered and washed with isopropanol . the resulting pink powder was dried under vacuum to give 97 % of the desired compound . other compounds prepared by a similar method described above include polyhydroxyl indoles such as fig1 , compound 5 , y 7 ═ so 3 − ; x 7 ═ h ; n = 2 this compound was prepared by the same procedure described in example 1 , except that 1 , 4 - butanesultone was used in place of 1 , 3 - propanesultone . fig2 , compound 8 , y 7 , y 8 ═ so 3 − ; x 7 ═ h ; n = 2 this compound was prepared by the same procedure described in example 1 , except that hydrazinonaphthalenedisulfonic acid was used in place of hydrazinobenzenesulfonic acid . other compounds prepared by a similar method include polyhydroxyindoles such as : fig2 , compound 8 , y 7 , y 8 ═ so 3 − ; x 7 ═ oh ; n = 4 this compound was prepared by the same procedure described in example 1 , except that 3 - hydroxymethyl - 4 - hydroxyl - 2 - butanone was used in place of 3 - methyl - 2 - butanone . a mixture of 1 , 1 , 2 - trimethyl -[ 1h ]- benz [ e ] indole ( 9 . 1 g , 43 . 58 mmoles ) and 3 - bromopropanoic acid ( 10 . 0 g , 65 . 37 mmoles ) in 1 , 2 - dichlorobenzene ( 40 ml ) was heated at 110 ° c . for 12 hours . the solution was cooled to room temperature and the red residue obtained was filtered and washed with acetonitrile : diethyl ether ( 1 : 1 ) mixture . the solid obtained was dried under vacuum to give 10 g ( 64 %) of light brown powder . a portion of this solid ( 6 . 0 g ; 16 . 56 mmoles ), glutaconaldehyde dianil monohydrochloride ( 2 . 36 g , 8 . 28 mmoles ) and sodium acetate trihydrate ( 2 . 93 g , 21 . 53 mmoles ) in ethanol ( 150 ml ) were refluxed for 90 minutes . after evaporating the solvent , 40 ml of 2 n aqueous hcl was added to the residue and the mixture was centrifuged and the supernatant was decanted . this procedure was repeated until the supernatant became nearly colorless . about 5 ml of water : acetonitrile ( 3 : 2 ) mixture was added to the solid residue and lyophilized to obtain 2 g of dark green flakes . the purity of the compound was established with 1 h - nmr and liquid chromatography / mass spectrometry ( lc / ms ). a mixture of 2 , 2 , 3 - trimethyl -[ 1h ]- benz [ e ] indole ( 20 g , 95 . 6 mmoles ) and 6 - bromohexanoic acid ( 28 . 1 g , 144 . 1 mmoles ) in 1 , 2 - dichlorobenzene ( 250 ml ) was heated at 110 c for 12 hours . the green solution was cooled to room temperature and the brown solid precipitate formed was collected by filtration . after washing the solid with 1 , 2 - dichlorobenzene and diethyl ether , the brown powder obtained ( 24 g , 64 %) was dried under vacuum at room temperature . a portion of this solid ( 4 . 0 g ; 9 . 8 mmoles ), glutaconaldehyde dianil monohydrochloride ( 1 . 4 g , 5 mmoles ) and sodium acetate trihydrate ( 1 . 8 g , 12 . 9 mmoles ) in ethanol ( 80 ml ) were refluxed for 1 hour . after evaporating the solvent , 20 ml of a 2 n aqueous hcl was added to the residue and the mixture was centrifuged and the supernatant was decanted . this procedure was repeated until the supernatant became nearly colorless . about 5 ml of water : acetonitrile ( 3 : 2 ) mixture was added to the solid residue and lyophilized to obtain about 2 g of dark green flakes . the purity of the compound was established with 1 h - nmr , hplc , and lc - ms . fig3 , compound 13 , y 7 , y 8 ═ o 3 − ; x 7 ═ oh ; n = 2 phosphorus oxychloride ( 37 ml , 0 . 4 mole ) was added dropwise with stirring to a cooled (− 2 ° c .) mixture of dimethylformamide ( dmf , 0 . 5 mole , 40 ml ) and dichloromethane ( dcm , 40 ml ), followed by the addition of acetone ( 5 . 8 g , 0 . 1 mole ). the ice bath was removed and the solution refluxed for 3 hours . after cooling to room temperature , the product was either partitioned in water / dcm , separated and dried , or was purified by fractional distillation . nuclear magnetic resonance and mass spectral analyses showed that the desired intermediate , 10 , was obtained . reaction of the intermediate with 2 equivalents of 2 , 2 , 3 - trimethyl -[ h ]- benz [ e ] indolesulfonate - n - propanoic acid and 2 equivalents of sodium acetate trihydrate in ethanol gave a blue - green solution after 1 . 5 hours at reflux . further functionalization of the dye with bis ( isopropylidene ) acetal protected monosaccharide is effected by the method described in the literature ( flanagan et al ., near infrared heavy - atom - modified fluorescent dyes for base - calling in dna - sequencing application using temporal discrimination . anal . chem ., 1998 , 70 ( 13 ), 2676 - 2684 ). fig4 , compound 16 , y 7 , y 8 ═ so 3 − ; x 7 ═ h ; n = 1 ) preparation of this compound was readily accomplished by the same procedure described in example 6 using p - hydroxybenzenesulfonic acid in the place of the monosaccharide , and benzoindole instead of indole derivatives . fig5 , compound 20 , y 7 , y 8 ═ h ; x 7 ═ oh ; n = 1 the hydroxyindole compound was readily prepared by a literature method ( southwick et a ., one pot fischer synthesis of ( 2 , 3 , 3 - trimethyl - 3 - h - indol - 5 - yl )- acetic acid derivatives as intermediates for fluorescent biolabels , org . prep . proced . int . briefs , 1988 , 20 ( 3 ), 279 - 284 ). reaction of p - carboxymethylphenylhydrazine hydrochloride ( 30 mmol , 1 equiv .) and 1 , 1 - bis ( hydroxymethyl ) propanone ( 45 mmol , 1 . 5 equiv .) in acetic acid ( 50 ml ) at room temperature for 30 minutes and at reflux for 1 gave ( 3 , 3 - dihydroxymethyl2 - methyl - 3 - h - indol - 5 - yl )- acetic acid as a solid residue . the intermediate 2 - chloro - 1 - formyl - 3 - hydroxymethylenecyclo - hexane was prepared as described in the literature ( reynolds and drexhage , stable heptamethine pyrylium dyes that absorb in the infrared . j . org . chem ., 1977 , 42 ( 5 ), 885 - 888 ). equal volumes ( 40 ml each ) of dimethylformamide ( dmf ) and dichloromethane were mixed and the solution was cooled to − 10 ° c . in acetone - dry ice bath . under argon atmosphere , phosphorus oxychloride ( 40 ml ) in dichloromethane was added dropwise to the cool dmf solution , followed by the addition of 10 g of cyclohexanone . the resulting solution was allowed to warm up to room temperature and heated at reflux for 6 hours . after cooling to room temperature , the mixture was poured into ice - cold water and stored at 4 ° c . for 12 hours . a yellow powder was obtained . condensation of a portion of this cyclic dialdehyde ( 1 equivalent ) with the indole intermediate ( 2 equivalents ) was carried out as described in example 5 . further , the functionalization of the dye with bis ( isopropylidene ) acetal protected monosaccharide was effected by the method described in the literature ( flanagan et al ., near infrared heavy - atom - modified fluorescent dyes for base - calling in dna - sequencing application using temporal discrimination . anal . chem ., 1998 , 70 ( 13 ), 2676 - 2684 ). fig6 , compound 22 , y 7 , y 8 ═ h ; x 7 ═ oh ; n = 1 a similar method described in example 8 was used to prepare this compound by replacing the indole with benzoindole derivatives . fig7 , compound 27 , y 7 , y 8 , x 7 ═ h ; n = 1 starting with 3 - oxo - 4 - cyclohexenone , this heteroatomic hydrophilic dye was readily prepared as described in example 8 . a laser of appropriate wavelength for excitation of the dye chromophore was directed into one end of a fiber optic bundle and the other end was positioned a few millimeters from the ear of a rat . a second fiber optic bundle was also positioned near the same ear to detect the emitted fluorescent light , and the other end was directed into the optics and electronics for data collection . an interference filter ( if ) in the collection optics train was used to select emitted fluorescent light of the appropriate wavelength for the dye chromophore . sprague - dawley or fischer 344 rats were anesthetized with urethane administered via intraperitoneal injection at a dose of 1 . 35 g / kg body weight . after the animals had achieved the desired plane of anesthesia , a 21 gauge butterfly with 12 ″ tubing was placed in the lateral tail vein of each animal and flushed with heparinized saline . the animals were placed onto a heating pad and kept warm throughout the entire study . the lobe of the left ear was affixed to a glass microscope slide to reduce movement and vibration . incident laser light delivered from the fiber optic was centered on the affixed ear . data acquisition was then initiated , and a background reading of fluorescence was obtained prior to administration of the test agent . the compound was administered to the animal through a bolus injection in the lateral tail vein . the dose was typically 0 . 05 to 20 μmole / kg of body weight . the fluorescence signal rapidly increased to a peak value , then decayed as a function of time as the conjugate cleared from the bloodstream . this procedure was repeated with several dye - peptide conjugates in normal and tumored rats . representative profiles are shown in fig6 - 10 . while the invention has been disclosed by reference to the details of preferred embodiments of the invention , it is to be understood that the disclosure is intended in an illustrative rather than in a limiting sense , as it is contemplated that modifications will readily occur to those skilled in the art , within the spirit of the invention and the scope of the appended claims .
highly hydrophilic indole and benzoindole derivatives that absorb and fluoresce in the visible region of light are disclosed . these compounds are useful for physiological and organ function monitoring . particularly , the molecules of the invention are useful for optical diagnosis of renal and cardiac diseases and for estimation of blood volume in vivo .