Showing papers on "Substituent published in 1988"

Biologically Produced (R)-3-Hydroxy- Alkanoate Polymers and Copolymers

Abstract: Microorganisms are capable of producing a wide range of polymers and copolymers based on 3-hydroxypropionic acid substituted with various alkyl groups in the 3-position. The most common homopolymer is poly (3-hydroxybutyrate), PHB, which has a 3-methyl substituent, but monomers having C2-C5 alkyl side groups are found in natural copolyesters. The monomers are all optically active in the r absolute configuration. Phb can be produced from carbon substrates as diverse as glucose, ethanol, acetate, methane and even gaseous mixtures of carbon dioxide and hydrogen. The polymer occurs as discrete granules within the cell cytoplasmic space and can represent up to 80% of the dry cell weight. After extraction and purification it behaves as a normal crystalline thermoplastic with a melting point around 180°C and can be processed by conventional extrusion and moulding equipment. PHB and its copolymers with 3-hydroxypentanoic acid are now available commercially and are being evaluated in numerous potential applications. The copolymers are all genuinely biodegradable in that their rate of chemical hydrolysis is extremely slow but microorganisms produce both specific and non-specific esterase enzymes capable of degrading the materials rapidly to non-toxic monomers. Most of the potential uses exploit this property in medical, veterinary, horticultural and general disposable products.

Molecular orbital approach to substituent effects in amine-CO2 interactions

Abstract: Effet des substituants de l'atome de carbone en position α, sur les proprietes de donneur des amines primaires et aminoalcools

Substituent Effects on the Cleavage Rates of Titanocene Metallacyclobutanes

Abstract: Effet des substituants des cyclopentadienyls sur la vitesse de reaction des t-butyl-3 di-η 5 -cyclopentadienyl-1,1 titanacyclobutanes avec le diphenylacetylene pour donner des di-η 5 -cyclopentadienyl-1,1 diphenyl-2,3 titanacyclobutenes-2 et le dimethyl-3,3 butene-1

Chiral smectic C liquid crystals having an electronegative substituent ortho to the chiral tail group - a study of a factor determining the magnitude of spontaneous polarization

Abstract: Chiral smectic C compounds having an ester group in the central core, an optically active tail group (alkoxy or alkoxycarbonyl), and an electronegative substituent (halogen or cyano) ortho to the chiral tail were synthesized. The effect of the ortho substitution on the characteristics, especially on spontaneous polarization (Ps), was examined. When the chiral tail is a 1-methylheptyloxy group the lateral substituent increases Ps relative to the unsubstituted analogue. In the case of 1-methylheptyloxycarbonyl tail group, however, the lateral substituent decreases Ps relative to the unsubstituted. These effects of lateral substituents are explained in terms of chemical structure of a single molecule, i. e., by taking statistical weight of conformers and the associated electric dipole moments into account.

Optical recording medium

Abstract: PURPOSE:To enhance sensitivity and reflectivity in a near infrared region and provide durability, by providing a recording layer comprising a specified phthalocyanine compound on a base. CONSTITUTION:On a base provided is a recording layer which comprises as a main constituent a phthalocyanine compound of the formula, namely, a phthalocyanine compound in which each of peripheral carbon atoms at specified positions of phthalocyanine is linked to one member selected from a specified group, while each of the other peripheral carbon atoms is linked to one member selected from another specified group, the number of the former peripheral carbon atoms thus linked being 2-8 and the number of the latter peripheral carbon atoms thus linked being 3-8. In the formula, numerals 1-16 denotes positions of the peripheral carbon atoms, K denotes substituent groups which may be the same or different, each of s, t, p and q is an integer of 0-4, each of the groups K corresponding to at least two of the peripheral carbon atoms at the positions 1, 4, 5, 8, 9, 12, 13 and 16 is a linked group P, which is -NH2, -NO2, -CN, -SO3Y, -SO1X or -X, and each of 3-8 carbon atoms of the peripheral carbon atoms at the positions 1-16 is a group (Z)rR, wherein Y is hydrogen or a metal atom, X is halogen, Z is -CH2, -CONHor -COO-, and R is a 4H-18C straight chain or branched alkyl or aryl; M is a metal, a metallic oxide or a halide of hydrogen and a metal; and r is 0 or 1.

New amino acid derivatives, processes for the preparation thereof and pharmaceutical composition comprising the same

Abstract: A compound of the formula : wherein R 1 is lower alkyl optionally substituted with a substituent selected from the group consisting of acyl,hydroxy, lower alkoxy, aryl, lower alkylthio and a group of the formula : in which R 5 is hydrogen or acyl and R 6 is hydrogen or lower alkyl; aryl; or amino optionally substituted with substituent(s) selected from the group consisting of lower alkyl and acyl; and R 2 is hydrogen or lower alkyl; or R 1 and R 2 are taken together with the attached nitrogen atom to form a heterocyclic group optionally substituted with substituent(s) selected from the group consisting of lower alkyl, hydroxy(lower)alkyl, lower alkoxy(lower)alkyl, acyl(lower)alkyl, oxo and acyl; R 3 is hydrogen or lower alkyl; and R 4 is lower alkyl; and its pharmaceutically acceptable salt, processes for the preparation thereof and pharmaceutical composition comprising the same.

Thiadiazoles useful in the treatment of senile dementia

Abstract: A class of novel thiadiazoles, substituted on one of the ring carbon atoms with a non-aromatic azacyclic or azabicyclic ring system, and substituted on the other ring carbon atom with a substituent of low lipophilicity, or a hydrocarbon substituent; are potent muscarinic agonists, and have good CNS penetrability. The compounds are therefore useful in the treatment of neurological and mental illnesses, and are also of benefit in the treatment of severe painful conditions.

Intermediates in the epoxidation of alkenes by cytochrome P-450 models. 2. Use of the trans-2,trans-3-diphenylcyclopropyl substituent in a search for radical intermediates

Abstract: Catalyse par les complexes: [(F 20 TPP)Fe(III)(Cl)], [(Cl 8 TPP)Fe(III)(Cl)], et [(Cl 8 TPP)Mn(III)(OH)]. (F 20 TPP=meso-tetrakis-pentafluorophenyl porphyrine, Cl 8 TPP=meso-tetrakis-[dichloro-2,6 phenyl] porphyrine)

Crystal structures and pharmacologic activities of 1,4-dihydropyridine calcium channel antagonists of the isobutyl methyl 2,6-dimethyl-4-(substituted phenyl)-1,4-dihydropyridine-3,5-dicarboxylate (nisoldipine) series.

Abstract: A series of isobutyl methyl 2,6-dimethyl-4-(X-substituted phenyl)-1,4-dihydropyridine-3,5-dicarboxylates (X = H, 2-NO2, 3-NO2, 3-CN, 3-MeO, 4-F, 2-CF3, 3-CF3, and 4-Cl) related to and including nisoldipine (X = 2-NO2) has been synthesized, their solid-state structures determined by X-ray analysis (X = H, 2-NO2, 3-NO2, 3-CN, 3-MeO, and 4-F), and their pharmacologic activities determined, as the racemic compounds, against [3H]nitrendipine binding and K+-depolarization-induced tension responses in intestinal smooth muscle as measures of Ca2+ channel antagonist activity. Comparisons of structure are presented to previously analyzed 1,4-dihydropyridines. The degree of 1,4-dihydropyridine ring puckering is dependent on the nature and position of the phenyl ring substituent and the adopted interring conformation. Different ester substituents affect 1,4-dihydropyridine ring puckering to a small extent in most cases. Pharmacologic and radioligand binding activities for the nine compounds studied show a parallel dependence on phenyl ring substituent, but the compounds are approximately 10-fold more active in the radioligand binding assay than in the pharmacologic assay. Consistent with a previous report for the nifedipine series (Fossheim et al. J. Med. Chem. 1982, 25, 126), pharmacologic activity increases with increasing 1,4-dihydropyridine ring planarity.

Cooling water corrosion inhibition method

Abstract: A method for inhibiting corrosion in industrial cooling waters which contain hardness and a pH of at least 6.5, by dosing the water with a composition which comprises a water-soluble inorganic phosphate capable of inhibiting corrosion in an aqueous alkaline environment and a hydrocarbon polymer containing an N-substituted acrylamide polymers with an amide structure as follows: ##STR1## where R 2 is hydrogen or methyl, where R 1 is a hydrogen or an alkyl and R is alkylene or phenylene, and X is sulfonate, (poly)hydroxyl, (poly)carboxyl or carbonyl, and combinations thereof; or containing derivatized maleic anhydride homo-, co- and terpolymers having N-substituted maleamic acid units, N-substituted maleimide units and maleic acid (and salts) units having a structure as follows: ##STR2## where R 1 , R 2 and R 3 are each independently chosen from the group consisting of hydrogen, hydroxyl, carboxyalkyl, carboxyamide, phenyl, substituted phenyl, linear or branched alkyl of from one to ten carbon atoms,and substituted alkyl of from one to ten carbon atoms, where the substituent is phosphonic acid; phosphinic acid; phosphate ester; sulfonic acid; sulfate ester, carboxyamide, (poly)carboxy and (poly)hydroxy, alkoxy and carboxylate ester groups; and combinations thereof.

Fulgides as Efficient Photochromic Compounds. Role of the Substituent on Furylalkylidene Moiety of Furylfulgides in the Photoreaction

Abstract: Quantum yields of photoreactions of furylfulgides having Me, Et, n-Pr, or i-Pr on the furylalkylidene moiety were measured. The E–Z isomerization was greatly suppressed and the cyclization was accelerated when the alkyl group (R) became bulkier. When R was i-Pr, no E–Z isomerization was observed and the quantum yield of the colorizing cyclization was 0.62.

Crystal structures and pharmacologic activities of 1,4-dihydropyridine calcium channel antagonists of the isobutyl methyl 2,6-dimethyl-4-(substituted phenyl)-1,4-dihydropyridine-3,5-dicarboxylate (nisoldipine) series

Abstract: A series of isobutyl methyl 2,6-dimethyl-4-(X-substituted phenyl)-1,4-dihydropyridine-3,5-dicarboxylates (X = H, 2-NO2, 3-NO2, 3-CN, 3-MeO, 4-F, 2-CF3, 3-CF3, and 4-Cl) related to and including nisoldipine (X = 2-NO2) has been synthesized, their solid-state structures determined by X-ray analysis (X = H, 2-NO2, 3-NO2, 3-CN, 3-MeO, and 4-F), and their pharmacologic activities determined, as the racemic compounds, against [3H]nitrendipine binding and K+-depolarization-induced tension responses in intestinal smooth muscle as measures of Ca2+ channel antagonist activity. Comparisons of structure are presented to previously analyzed 1,4-dihydropyridines. The degree of 1,4-dihydropyridine ring puckering is dependent on the nature and position of the phenyl ring substituent and the adopted interring conformation. Different ester substituents affect 1,4-dihydropyridine ring puckering to a small extent in most cases. Pharmacologic and radioligand binding activities for the nine compounds studied show a parallel dependence on phenyl ring substituent, but the compounds are approximately 10-fold more active in the radioligand binding assay than in the pharmacologic assay. Consistent with a previous report for the nifedipine series (Fossheim et al. J. Med. Chem. 1982, 25, 126), pharmacologic activity increases with increasing 1,4-dihydropyridine ring planarity.

Enzymatically-cleavable chemiluminescent fused polycyclic ring-containing 1,2-dioxetanes

Abstract: Chemiluminescent 1,2-dioxetane compounds are disclosed in which the molecule is stabilized at the 3-position on the dioxetane ring against decomposition prior to the molecule's coming in contact with a labile group-removing substance (e.g., an enzyme that will cleave the labile group to cause the molecule to decompose to form at least one light-emitting fluorophore) and substituted at the 4-position on the dioxetane ring with a fused polycyclic ring-containing fluorophore moiety bearing a labile ring substituent whose point of attachment to the fused polycyclic ring, in relation to this ring's point(s) of attachment to the dioxetane ring, is such that the total number of ring atoms separating these points of attachment, including the ring atoms at the points of attachment, is an odd whole number. These odd pattern substituted compounds decompose to emit light of greater intensity and of a different wavelength than that emitted by the corresponding even pattern substituted isomers. They are useful in detecting the presence or determining the concentration of chemical or biological substances in immunoassays, chemical assays and nucleic acid probe assays, and in chemical/physical probe procedures for studying the microstructures of macromolecules. Two or more of them can also be used in combination, or one or more of them can be used together with other chemiluminescent compounds, in multi-channel assays to detect two or more different analytes simultaneously. Novel intermediates used in the preparation of these odd pattern substituted compounds are also disclosed.

Substituent effects on .eta.2-coordinated arene complexes of pentaammineosmium(II)

Abstract: (NH 3 ) 5 Os 2+ reagit avec les benzenes substitues pour donner des complexes dans lesquels l'arene est coordine a l'Os. Grande stabilite de ces complexes

Kinetics and substituent effects in the formation of zirconocene thioaldehyde complexes: .beta.-hydride elimination versus cyclometalation

Abstract: Effet des substituants en position para de l'α-toluenethiolate du complexe alkylthio de depart

Captodative Substituent Effect .45. Captodative Substituent Effects in Radical Chemistry

Abstract: Polar substituents are gen'erally more efficient for the stabil.isation of ions than for radicals. These last species are more and more recognised as inmortant intermediates in chemistry and in biochemistry. The cumulative effect of two substituents of the same polarity shows antagonism for radical. stabilisation whereas captodative (cd) substituents show synergy. Synthetic applications of the cd-effect use the breaking of adjacent weak \"proradical\" C-H and C-C bonds. Further, cd-double bonds are useful as radical traps and as partners in cycloaddition reactions. cd-N-vinyl. substitution induces with complete stereocontrol. the epoxy-epimination rearrangement of chiral oxazines and opens a new route to inosite and streptamine derivatives. 1636 H. G. VIEHE, R. MERENYI AND 2. JANOUSEK OM(/CN CM/OMe SR /CN NH7/CN COOEt/NISir* 3) COOEt/OH SMe /COO Et OMe/COOEt cd-Dichloromethylene compounds with aminosubstituents as dative group have l.ittle ionic character but do display it in substitution reactions with nucleophiles if the rearrangement is avoided, for example, by temperature control. With the CF3-group as captor group potential. a-trifluoromethyl-cations are available both before and after the rearrangement which takes place around 1.OO0C (ref. 6) (Fig. 3). + 1.0 + 5.17 + 16.0 + 6.91 0.3 + 13.0 + L.2 + 9.6 + 12.8 1 7.6 + 2.6 + 0.8 re f 8 ' O o'*I 9 I % Fig. 3 C H3C I

substituted aralkyl) heterocyclic compounds

Abstract: A (substituted-aralkyl)heterocyclic compound of the formula I ##STR1## wherein R 1 is an azido, carbamoyl, cyano, formyl, hydroxy or nitro radical, a 1-6C 1-hydroxyalkyl, alkoxy, alkylcarbamoyl, alkylthio, alkylsulphinyl or alkylsulphonyl radical, a 2-cyanoethyl radical, optionally bearing one to four 1-6C alkyl substituents, or a 2-6C alkanoyl, halogenoalkanoyl, alkanoyloxy, alkanoylamino, dialkylcarbamoyl or alkoxycarbonyl radical; R 2 and R 3 , which may be the same or different, are each a hydrogen atom, a 1-6C alkyl, dueterioalkyl or halogenoalkyl radical, or a phenyl or phenyl(1-6C alkyl) radical, in each of which the phenyl may optionally bear one or more substituents; or R 2 and R 3 , together with the carbon atom to which they are attached, may form a 3- to 6-membered ring; or R 1 R 2 R 3 C- is a 1,1-dicyanoethyl or trifluoromethylsulphonyl radical; R 4 is a hydrogen or halogen atom, a cyano or nitro radical or a 1-6C alkyl or halogenoalkyl radical; R 5 has any of the values defined above for the group R 1 R 2 R 3 C but is not necessarily the same as R 1 R 2 R 3 C, or has any of the values defined above for R 4 but is not necesarily the same as R 4 , or is a carbamoyl, 1-pyrrolidinyl-carbonyl, piperidinocarbonyl, morpholinocarbonyl or nitro radical, a 1-6C alkoxy or halogenoalkoxy radical or a 2-6C alkanoyl or alkoxy-carbonyl radical; A is a methylene or ethylene radical optionally bearing one or more substituents selected from deuterium and halogen atoms, carbamoyl, cyano and hydroxy radicals, 1-6C alkyl and alkoxy radicals, and 2-6C alkanoyloxy radicals provided that when A is linked to R 6 through a nitrogen atom thereof, it may not bear a hydroxy, alkoxy or alkanoyloxy substituent on the carbon atom adjacent to such nitrogen atoms; and R 6 is a 1H-1,2,4-triazol-1-yl, 4H-1,2,4-triazol-4-yl, 1H-imidazol-1-yl, 5-cyano-1H-imidazol-1-yl, 3-pyridyl or 5-pyrimidinyl radical, or a 1H-imidazol-1-yl radical, bearing at the 5-position thereof a 1-6C alkyl substituent which is itself optionally substituted by one or more carbamoyl, cyano, hydroxy or 2-6C alkoxycarbonyl radicals; and provided that when R 2 , R 3 , R 4 and R 5 are hydrogen, A is a methylene radical and R 6 is a 3-pyridyl radical, R 1 is not a cyano, hydroxy or hydroxymethyl radical, and when R 1 is a hydroxy radical, R 3 , R 4 and R 5 are hydrogen, A is a methylene radical and R 6 is 3-pyridyl, R 2 is not a methyl or a 2-chloro-1-methylethyl radical, and provided that when R 1 is a methoxycarbonyl radical, R 2 , R 3 , R 4 and R 5 are hydrogen and A is a methylene radical, R 1 is not a 1H-imidazol-1-yl radical; and the pharmaceutically acceptable acid addition salts thereof.

Addition of arylchlorocarbenes to α,β-unsaturated esters. Absolute rates, substituent effects, and variable reactivities

Abstract: La reaction des (aryl chloro) methylenes avec le maleate de diethyle produit des (aryl-3 chloro-3)cyclopropanedicarboxylates-1,2 de diethyle