Pyridyl esters

After having been cooled it is washed three times in water, three times in a 5% solution of caustic soda, and then another three times in water. The solution in xylene is dried over sodium sulfate and the xylene is completely distilled off in vacuo. Thus 11.0 parts of hexa-methylene-bis-(N-methyl carbamic acid-3-pyridyl ester) are obtained. 

S.P. solid-phase technique L.P. liquid-phase technique OPTcp pentachlorophenyl ester TEEP tetraethyl pyrophosphit OTCp trichlorophenyl ester ONp p-nitrophenyl ester ONSu N-hydroxysuccinimido ester OPFp pentafluorophenyl ester OQu 8-hydroxyquinyl ester OPy 3-hydroxy-pyridyl ester ODnp 2,4-dinitrophenyl ester DCC dicyclohexylcarbodiimide HOBn 3-hydroxy-4-oxo-3,4-dihydro-l,2,3-benzotriazin Opi JV-hy-droxypiperidine EEDQ 2-ethoxy-l-ethoxycarbonyl-l,2-dihydroquinoline Tos p-toluenesulfonyl PTC propanetricarboxylic acid OBu tm-butyl ester Nva norvaline Aha aminohexanoic acid Om ornithine... 

Scheme 6.8 gives some examples of ketene-alkene cycloadditions. In Entry 1, dimethylketene was generated by pyrolysis of the dimer, 2,2,4,4-tetramethylcyclobutane-l,3-dione and passed into a solution of the alkene maintained at 70° C. Entries 2 and 3 involve generation of chloromethylketene by dehydrohalo-genation of a-chloropropanoyl chloride. Entry 4 involves formation of dichloroketene. Entry 5 is an intramolecular addition, with the ketene being generated from a 2-pyridyl ester. Entries 6, 7, and 8 are other examples of intramolecular ketene additions. 

Irreversible inhibition is probably due to the alkylation of a histidine residue.43 Chymotrypsin is selectively inactivated with no or poor inhibition of human leukocyte elastase (HLE) with a major difference the inactivation of HLE is transient.42,43 The calculated intrinsic reactivity of the coumarin derivatives, using a model of a nucleophilic reaction between the ligand and the methanol-water pair, indicates that the inhibitor potency cannot be explained solely by differences in the reactivity of the lactonic carbonyl group toward the nucleophilic attack 43 Studies on pyridyl esters of 6-(chloromethyl)-2-oxo-2//-1 -benzopyran-3-carboxylic acid (5 and 6, Fig. 11.5) and related structures having various substituents at the 6-position (7, Fig. 11.5) revealed that compounds 5 and 6 are powerful inhibitors of human leukocyte elastase and a-chymotrypsin thrombin is inhibited in some cases whereas trypsin is not inhibited.21... 

Benzene addition to Ir(P Pr3)2Cl is an exothermic reaction (22kcal mol-1), while addition to Ir(P Pr3)2(CO)Cl is endothermic (—5kcal mol-1).501 The reaction enthalpies of substitution reactions to complexes containing the Ir(P1Pr3)2Cl fragment are supplied. Reaction of Ir(P1Pr3)2Cl with 2-pyridyl esters gives a p2 (C,0)-bound ketene, (307), where R2 = R1 = aryl or R2 = aryl,... 

Synonyms AI3-27311 BRN 1545756 Brodan Caswell No. 219AA CCRIS 7144 Chloryrifos-ethyl Coroban Detmol U.A. 0,0-Diethyl-0-3,5,6-trichloro-2-pyridyl phosphorothioate Dowco-179 Dursban Dursban F EINECS 220-864-4 ENT 27311 Eradex Grofo Killmaster Lentrek Lorsban NA 2783 QMS 971 Phosphorothionic acid, 0,0-diethyl 0-(3,5,6-trichloro-2-pyridyl) ester Pyrinex Terial UN 2783 XRM 429 XRM 5160. 

Phosphorothionic acid, 00-diethyl 0-(3,5,6-trichloro-2-pyridyl) ester, see Chlorpyrifos Phosphostigmine, see Parathion Phosphothion, see Malathion Phosvit, see Dichlorvos Phthalandione, see Phthalic anhydride... 

HI - PHOSPHOROTNIOIC ACID, 0,0-DIETHYL 0-(3,5,6-TRICHLORO-2-PYRIDYL) ESTER... 

Meanwhile, Mukaiyama et al. [26] developed another similar procedure, by the use of 6-phenyl-2-pyridyl esters, for the synthesis of macrocychc lactones. This method has been used in the synthesis of f - - )-ricinelaidic acid lactone 40) [27]. Thus, as shown in Scheme 13, a mixture of 6-phenyl-2-pyridone, 2-chloro-l-methylpyridinium iodide 28), and triethylamine in dichloromethane was stirred at room temperature for 1 h. To this solution was added a dichloromethane solution of the hydroxy acid 38 and triethylamine under reflux over 6 h to give the activated ester 39 in 99% yield. A dichloromethane solution of 39 was added to a / -toluenesulfonic acid solution in dichloromethane under reflux over 11 h. Acid-induced lactonization led to the macrocycle 40 in 96% yield ... 

Ketone synthesis.4 Organocuprates do not ordinarily react with esters at low temperatures, but they react satisfactorily with 2-pyridyl esters to provide ketones. These esters are readily available by reaction of 2-pyridyl chloroformate, an acid, and N(C2H5)3 catalyzed by DMAP. 

Thiopropansaure 2-(tert.-Butyloxy-carbonyl-amino)- -S-(2-pyridyl-ester) XV/2, 283 f. 

Recognition of the value of active esters for peptide bond formation emerged from work with vinyl esters ly cyanomethyl esters 5-phenyl thioesters 9,P1 piperidino esters 10, 3-pyridyl esters 4-nitrophenyl esters 12 2,4,6-trichlorophenyl esters,and phthalimido esters 17.t l Many activating moieties have surfaced over the years but only a limited number have survived the test of time and are in use today. These include 4-nitrophenyl 12,M 2,4,5-trichlorophenyl pentachlorophenyl pentafluorophenyl succininoido... 

In general, salt-free solutions of ylides do not react with methyl or ethyl esters of carboxylic acids. Better results can be obtained when activated esters (e.g. phenyl or pyridyl esters) are used for acyl-ation. " Acylation with carboxylic acid anhydrides also requires only one mole of starting ylide (equation 73). ... 

Indium-mediated coupling of allylic bromides with acyUmidazoles or -pyra-zoles in aqueous media gives the corresponding ketones (Scheme 8.46) [68]. Indium-mediated allylation of acyl cyanides with allyl halides in aqueous media affords a variety of /fy-urisaturalcd ketones (Scheme 8.47) [69]. Indium is effective in 2-pyridyl esters with allyl bromides or with iodide in pure water (Scheme 8.48) [70]. 

Pyridyl esters 200 (R = COMe, COPh, COCF3) and nitrophenyl ethers react with benzyne to give 196.103 [Theether200(R = 2,4-dinitrophenyl) was for some time mistakenly believed to be the betaine, l-(2,4-dinitrophenyl)-pyridinium 3-oxide, and its reaction with benzyne was at first ascribed to the... 

Oowco 217 ENT 27521 EPA Pesticide Chemicai Code 103501 Fospirat Fospirate Fospirate methyl Fospiralo Fospiratum NSC 195058 OMS 1188 Phosphoric acid, dimethyi 3,6,6-trichloro-2-pyridyl ester Toreile. Anthelmintic. Registered by EPA as an insecticide (cancelied), Crystais mp = 86.5 88°. Dow AgroSciences Dow UK. 

Bei dieser Oxidations-Reduktions-Kondensation entstehen aus aliphatischen und aromatischen Carbonsauren in hohen Ausbeuten die entsprechenden S-(2-Pyridyl)-ester. Neben der Herstellung von S-Estern wird die Oxidations-Reduktions-Kondensation u.a. zur Synthese von Peptiden, Nucleotiden und Makroliden62 sowie bei der Totalsynthese von Coenzym A63 herangezogen. 

Esters and lactones. Treatment of the 2-pyridyl ester of a thiocarboxylic... 

Esters and lactones. Treatment of the 2-pyridyl ester of a thiocarboxylic S-acid such as (1), prepzured as shown, with either silver tetrafluoroborate or silver... 

Results from CoMFA studies have been compared with those from Hansch analyses [38, 1019 — 1023] and the minimal topological difference (MTD) method [1024]. Examples for the comparison of Hansch equations with CoMFA studies are e.g. the papain hydrolysis of N-(X-benzoyl)glycine pyridyl esters (60) (eqs. 204, 205 Zn = PLS component n of the corresponding field compare chapter 7.1) [1019, 1020], the emulsin-catalyzed hydrolysis of phenyl-P-D-glucosides [1020], the mutagenic activities of substituted (o-phenylenediamine)platinum dichlorides [1020], dihydrofolate reductase (DHFR) inhibition [1020], and some other biological activities [38, 1021—1023]. 

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