Pyrimidine is a heterocyclic aromatic organic compound similar to benzene and pyridine, containing two nitrogen atoms at positions 1 3 of the six-member ring. Three nucleobases found in nucleic acids, cytosine (C), thymine (T), uracil (U), are pyrimidine derivatives. A has many properties common with as number ring increases pi electrons become less energetic electrophilic substitution gets mor...

HIE-124 is a new member of ultra-short acting hypnotics’ drug family. In this research, the synthesis ofanalogues of HIE-124 drug in the heterocyclic thiazole ring replaced to thiadiazole, will be presented.Thiadiazolodiazepines during a two-step reaction starting from the amino thiadiazole resultedfrom-various derivatives of benzoic acid and thiosemicarbazide were synthesized. In the first ste...

A practical and efficient route to the CD spiroketal (C-16-C-28) of the spongistatins is reported. Two stereocenters are introduced from chiral building blocks with the remainder introduced by substrate-controlled transformations. The key beta-keto-1,3-dithiane intermediate is generated by a dithiol conjugate addition to an ynone and the 1,3-dithiane unit in the C-ring plays a key role in the s...

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Feeding experiments with a mixture of [2-13C]- and [indole-3-13C]tryptophans, of [3-13C]- and [indole-3-13 C]tryptophans (1:1 molar ratio) and of others have proved that the 1,2-shift of the indole ring occurred via an intramolecular process for formation of the left part (5-hydroxyindole side) of the violacein skeleton and demonstrated that the C-C bond from C2 of the indole ring to C2 of the ...

Studies for this thesis involve efforts toward the enantioselective total synthesis of taxusin (5). Key features of the synthetic sequence include a diastereoselective, intramolecular enone-olefin [2+2] photocyclization of photosubstrate 94 which introduces the correct stereochemistry of the C(8) methyl group. This reaction represents an unprecedented total reversal of stereochemistry from the ...

The first enantioselective total synthesis of the cytotoxic natural product (+)-psiguadial B is reported. Key features of the synthesis include (1) the enantioselective preparation of a key cyclobutane intermediate by a tandem Wolff rearrangement/asymmetric ketene addition, (2) a directed C(sp(3))-H alkenylation reaction to strategically forge the C1-C2 bond, and (3) a ring-closing metathesis t...

A ring R is uniquely (nil) clean in case for any $a in R$ there exists a uniquely idempotent $ein R$ such that $a-e$ is invertible (nilpotent). Let $C =(A V W B)$ be the Morita Context ring. We determine conditions under which the rings $A,B$ are uniquely (nil) clean. Moreover we show that the center of a uniquely (nil) clean ring is uniquely (nil) clean.