Kondareddiar Ramalingam

A convenient synthesis of s-(5′-deoxy-5′-adenosyl)- (±) -2-methylhomocysteine

Abstract The synthesis of S -(5′-deoxy-5′-adenosyl)-+-2-methylhomocysteine in two steps from +- -2-methylmethionine is described.

A practical large scale chemical synthesis of chiral glycines

Abstract (R)- and (S)-[2-2H]glycine of high chiral purity were synthesized in large quantities in ≈ 40% overall yield from readily available starting materials via a totally chemical procedure. Reduction of either [1-2H]-furfural or [1-2H]-4-methoxybenzaldehyde with either (+) or (-)-B-isopinocampheyl-9-borabicyclo[3.3.1]nonane gave chiral arylmethyl alcohols which were converted into their respective phthaloyl amino derivatives of the opposite configuration at the methylene carbon via the Mitsunobu reaction. The aromatic groups were oxidatively unmasked to give their corresponding glycine derivatives by either ozone or ruthenium tetraoxide oxidation.

A Facile Procedure for the Preparation of Alicyclic α-Amino Acids

Abstract A Convenient method for the preparation of alicyclic α-amino adds is described which utilizes ethyl isocyanoacetate and the appropriate dibromo-substituted aliphatic alkylatlng agent.

Alternate substrates and inhibitors of 1-aminocyclopropane-1-carboxylic acid synthase

Abstract Structural analogs of (−)- S -adenosyl- l -methionine (SAM), in which the heterocyclic base was modified, were used to initiate studies to elucidate the active site conformation of the enzyme 1-aminocyclopropane-1-carboxylic acid (ACC) synthase, which was partially purified from Lycopersicon esculentum (tomato). These potential substrate analogs were screened for activity both as substrates and/or as inhibitors of ACC synthase. In general, ACC synthase was found to have a rather rigid specificity for the structural features of the natural substrate (SAM) in that only the purine base adenosine and adenosine analogs in which the N 6 nitrogen was modified were substrates.

The proton NMR assignment of 1-aminocyclo-propane-1-carboxylic acid

Abstract The two sets of diastereomeric hydrogen atoms cis and trans to the carboxylate of 1-aminocyclopropane-1-carboxylic acid (ACC) were differentiated by a 1H-nmr study. The measurement of the 1H-nmr spectrum of ACC at pH 3.8 during the successive addition of non-chiral lanthanide reagents such as Eu(NO3)3, Pr(NO3)3 or Gd(NO3)3 demonstrated that the hydrogen atoms cis to the carboxylate function of ACC resonate at δ=1.42 and that the hydrogen atoms trans to the carboxylate function of ACC resonate at δ=1.20. The mono-substituted cyclopropanes, cyclo-propanecarboxylic acid (CPC) and cyclopropyl-amine (CPA) were used in complementary lanthanide-reagent shift titrations along with the back titration of an ACC-Eu+++ complex with DCl to further substantiate the assignment. This assignment allows for the non-destructive, nonisotopic diluting analysis of various biosynthetically derived deuterated ACCs formed from the corresponding deuterated S-adenosyl-L-methionine.