نتایج جستجو برای: intermediate c ring
تعداد نتایج: 1259952 فیلتر نتایج به سال:
Four methanofullerene derivatives, with phosphonate or sulfone groups attached to a C(60) core through a Bingel procedure, were synthesized to probe their stability upon electrolytic reduction. Derivatives 1 and 2 are the most stable upon electroreduction and do not exhibit retro-cyclopropanation reactions until more than three electrons per C(60) derivative are transferred. The cyclopropane ri...
Prazosin (2-[4-(2-furanoyl)-piperazin-1-yl]-4-amino-6,7-dimethoxyquinazoline) is an antihypertensive agent that was introduced to the market in 1976. It has since established an excellent safety record. However, in vitro metabolism of prazosin has not been investigated. This study describes the in vitro biotransformation of prazosin in liver microsomes from rats, dogs, and humans, as well as ra...
Let $C$ be a semidualizing module. We first investigate the properties of finitely generated $G_C$-projective modules. Then, relative to $C$, we introduce and study the rings over which every submodule of a projective (flat) module is $G_C$-projective (flat), which we call $C$-Gorenstein (semi)hereditary rings. It is proved that every $C$-Gorenstein hereditary ring is both cohe...
The main result of this paper is a generalization the theorem Chevalley-Shephard-Todd to rings invariants pseudoreflection groups over Dedekind domains. In special case principal ideal domain in which group order invertible it proved that ring isomorphic polynomial ring. An intermediate every finitely generated regular graded algebra tensor product blowup algebras.
We have measured the infra-red absorption spectra of chlorophyll and some of its derivatives in order to obtain information useful for eventual understanding of reversible transformations of this pigment. Such transformations are (a) Moliseh phase test, (b) bleaching by FeCl3, and (c) photochemical reduction by ascorbic acid-"Krasnovsky reaction" (10, 13, 16). Only in the case of the phase test...
conclusions trim22 gene ring domain -364t/c polymorphism is associated with chronic hbv infection in chinese han population. results 243 (31.76%) of 765 chinese han patients showed genetic variation in the trim22 gene. trim22 snps were mainly in ring area -364t/c site, accounting for 98.35% of the population. there were no significant differences (p > 0.05) in the ring domain -364t/c snp and al...
this study represents a highly efficient and regioselective ring-opening of epoxides with acetic anhydride in the presence of naoac·3h2o at solvent-free conditions. the ring-opening of different classes of epoxides were carried in oil bath (70-80 °c) to afford 1,2-diacetates in high to excellent yields
In this research at the first complex and its halogenated derivatives were optimized. NBO calculations and NMR for the complexes were carried out at the B3LYP/6-31G*quantum chemistry level. In the 1- (4-fluorophenyl) -2, 3-dihydro-1 H-naphto- [1, 2-e] [1, 3] oxazine-3-n, there are 4 rings, respectively, rings from the side attached to the halogen They are named C, B, A, and D. Calculations and ...
An enantioselective route to four tricyclic amino acids and N-tosylamides, composed of a central norbornane framework with a 2-endo,3-endo-annelated pyrrolidine ring and a 5-endo-C₁ or -C₂ side chain, has been developed. A key intermediate was the chiral, N-Boc-protected ketone (1R,2S,6S,7R)-4-azatricyclo[5.2.1.0²,⁶]decan-8-one, available from inexpensive endo-carbic anhydride in five steps and...
We describe a new synthesis of the 3-chloro-(4'-methoxy)-2,2'-pyrrolylfuran segment (3) of (+)- roseophilin. The route exploits a isoxazoylpyrrole intermediate, wherein the isoxazole ring serves as a β-diketone equivalent and a directing group for palladium catalyzed chlorination of the attached pyrrole. Subsequent reduction of the N-O bond and acid promoted cyclization afords roseophilin segme...
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