We have examined the reactivities of α-phosphorylmethyl benzothiazolyl sulfoxides in the thermolyses and in the presence of several amines, such as aniline, benzylamine, piperidine, morpholine, and pyrrolidine. Thermolyses of the derivatives in the presence of 2,3-dimethyl-1,3-butadiene afforde...

Prolonged treatment of menth-4-en-3-yl sulfides with H2O2 in acidic medium leads to saturated menthan-3-yl sulfones, the same products having been obtained from menth-4-en-3-yl sulfoxides in acidic medium in the absence of H2O2. The mechanism was evaluated by quantum chemical calculations.

The five possible isolated-pentagon fullerene isomers of C78 are investigated employing the Hartree—Fock self-consistent field method with minimal and double-zeta quality basis sets. Of the five structures, two have C2v symmetry (C2v(I) and C2v(II)), two others have D3h symmetry (D3h(I) and D3h...

Semi-empirical and ab initio calculations are reported for the five C78 fullerenes with isolated pentagons. The optimized geometries and relative stabilities are discussed. The D3h structure previously favored on the basis of simple Hückel arguments is found to be the least stable isomer at all...

The characteristic polynomials of five preferable fullerene cages with isolated pentagons are computed and compared. It is shown that one needs at least the twelfth coefficient in the characteristic polynomial to discriminate the five isomers. Exact formulas are aslo provided for the first nine ...

We report on new stable polymerized fullerites consisting of large fullerenes. Using the empirical many-body model potential for C atoms, we find that C74 and C78(C2v′) fullerenes possess stable infinite covalent networks in which C74 and C78 fullerenes form two-dimensional hexagonal lattice an...

Geometric and electronic structures of C78 fullerenes encapsulating two Ti atoms and a C2 molecule are studied by the first-principle total energy calculations. We find that the substantial hybridization between the 3d state of Ti atoms and the 2p state of C atoms results in the formation of wea...

Based on first-principles total energy calculations, we analyze the energetics of the fullerene isomers from C60 to C78, all of which satisfy the isolated pentagon rule, under a parallel electric field. Our calculations show that the total energy of the fullerene is proportional to the square of...

Addition patterns of isomeric C78(1)Cl30 and C78(2)Cl30 respectively show striking differences, which concern the formation of extended vs. small ring aromatic systems, the presence vs. the absence of triple Cl···Cl contacts and chlorinated sites of triple hexagon junctions.

Wang resin was modified by (1R,2R)-(+)-1,2-DPEN by means of a triazine ring. The catalyst was characterized by thermogravimetric (TG) analysis, elemental analysis, and Fourier transform infrared spectroscopy (FT-IR). Subsequently, this catalyst was employed for the asymmetric Michael addition of...

Synthetic routes to all four diastereoisomers of 3-thymine-1-(tbutoxycarbonyl)aminocyclopentane-1-carboxylic acid have been developed starting from the commercially available (S)-dimethyl malate. The key step in the synthesis involves dialkylation of N-(diphenylmethylene)glycine ethyl ester with...

As a neurotransmitter, the amino acid glutamate has been the subject of efforts to generate structural analogs with unique properties. Here we report a practical, half-gram synthesis of two cyclopropene-containing glutamate analogs. These analogs are stable in solution, in the presence of the bi...

Conformationally restricted pyrrolidinyl PNAs with an α/β-dipeptide backbone consisting of a nucleobase-modified proline and a cyclic five-membered amino acid spacer such as (1S,2S)-2-aminocyclopentanecarboxylic acid (ACPC) (acpcPNA) can form very stable hybrids with DNA with high Watson–Cric...

Peptide formation on the N-terminal of 1-aminoazetidine-2-carboxylic acid is rendered problematic due to a ring opening reaction. However C-terminal development is possible and two diastereomeric mixed hydrazino dipeptides were prepared. Solution-state studies of these compounds suggest the pres...

Racemic trans 3-(9-fluorenylmethyloxycarbonylamino)-1-oxyl-2,2,5,5-tetramethylpyrrolidine-4-carboxylic acid (Fmoc-POAC-OH), prepared by conventional methods, was resolved upon esterification with (aR)-2,2′-dihydroxy-1,1′-binaphthyl. Separation of the obtained diastereomeric monoesters Fmoc-(±...

N,N-Dibenzylamino aldehydes 1 react with Reformatsky's reagent leading to anti-γ-dibenzylamino-β-hydroxy esters 2 as the major stereoisomers. Treatment of 2 with TFA followed by hydrogenolysis on Pearlman's catalyst yields the corresponding γ-amino-β-hydroxy acids 10. Contrarily, s...

Syntheses of cis-3-alkylaziridine-2-carboxylates including cis-3-benzyl- and cis-3-phenylaziridine-2-carboxylates were achieved from the reaction of α-aminonitrile and alkyldiazoacetate in the presence of a Lewis acid. Asymmetric version of this reaction with the chiral α-methylbenzylamine was...

The title cyclic β-amino esters were synthesized stereo- and regioselectively. Starting from the corresponding 1-aryl- and 1-alkylcyclopropane-1,2-dicarboxylates, selective monosaponification and subsequent Curtius reaction leads to certain cis-1-alkyl- and 1-aryl-2-aminocyclopropanecarboxylic ...

The synthesis of orthogonally protected β-amino acid 3-tert-butoxycarbonylamino-1,2,3,4-tetrahydro-2-naphthoic acid benzyl ester (Boc-βAtc-OBn) is described. The route to these constrained phenylalanine analogs features a SmI2-mediated aziridine cleavage resulting in a β-amino ester. The ster...

To further determine absolute configurations of versicolactones A and B, total synthesis of versicolactones A and B and their six stereoisomers were reported in this Letter. The 1H and 13C NMR spectra of the synthetic erythro-stereoisomers matched perfectly with those of the natural products. Co...