József Tamás

Ring transformations of 1,3-benzothiazine derivatives II conversion of 6α-aryl-7α-chloro-2,3(2′,3′-dialkqxybenzo)-1-thiaoctems3 into 2-carbomethoxy-3-aryl-7,8-dialkoxy-4.5-dihydro-1,4-benzothiazepines

Abstract 6,7-Dialkoxy-2-aryl-4 H 1-1,3-benzothiazines (1a⇍) react with chloroacetyl chlorlde to give condensed β-lactam derivatives (2a⇍). Basic treatment of 2a⇍ in methanol led to the corresponding 1,4-banzothiazepine derivativee (3a⇍) via ring expansion. The structures of the products were determined by IR, NMR and MS studies

Synthesis of vinca alkaloids and related compounds—XVI: New route to the stereoselective synthesis of (+)-vincamine, (-)-vincamone and (+)-apovincaminic acid esters

Abstract A stereoselective method has been elaborated for the synthesis of oxime esters, (-)-4a, b, from which, as common intermediates, (+)-apovincaminic acid esters (3a,b), (+)-vincamine (1) and (-)-vincamone (2) can be prepared.

A synthesis of l-ristosamine and a derivative of its C-4 epimer

Abstract A synthesis of l -ristosamine from l -rhamnal is described, involving the sequence of reactions: methoxymercuration, tosylation, azide displacement, and reduction, which gave methyl α- l -ristosaminide (10) . Acid hydrolysis then afforded l -ristosamine hydrochloride. Trifluoroacetylation of the hydrochloride of 10 followed by saponification and oxidation with ruthenium tetraoxide gave methyl 2,3,6-tri-deoxy-3-trifluoroacetamido-α- l - erythro -hexopyranosid-4-ulose (17). Borohydride reduction of 17 gave a separable, 1:1 mixture of methyl 2,3,6-trideoxy-3-trifluoroacetamido-α- l - ribo - and α- l - xylo -hexopyranoside.

Metabolism of mesocarb in the rat

1. Rats treated orally with [14C]mesocarb (I; 3-(1-methyl-2-phenyl[2-(14C]ethyl)-N-(phenylaminocarbonyl)sydnone imine) (50 mg/kg) excrete 35% of the radioactivity in 24 h urine and 51% in 48 h urine. 2. Only traces of unchanged drug were found in urine. Hydroxy-mesocarb (II), dihydroxy-mesocarb (III), amphetamine (VII) and the conjugates of II and III account for 86% of the urinary radioactivity. 3. Cannulated male rats excrete about 40% of the radioactivity in 30 h in bile, mainly as conjugates of II and III.

Achillicin, the first proazulene from Achillea millefolium

Abstract Achillicin, the major proazulene (prochamazulene) of Achillea millefolium L. ssp. collina Becker has been isolated and identified as 8-acetoxyartabsin. It is the first proazulene reported for the genus Achillea and has not been found previously in plants.

Synthesis of D-ristosamine and its derivatives

Abstract A convenient preparative route involving eleven steps starting from D -glucose is described for the synthesis of D -ristosamine ( 15 ) hydrochloride. Methyl 2-deoxy-β- D - arabino -hexopyranoside, prepared from 3,4,6-tri- O -acetyl-1,5-anhydro-2-deoxy- D - arabino -hex- 1-enitol, was benzylidenated, and the product mesylated to give methyl 4,6- O -benzylidene-2-deoxy-3- O -methylsulfonyl-β- D - arabino -hexopyranoside. Azidolysis of this compound and subsequent opening of the 1,3-dioxane ring with N -bromosuccinimide gave methyl 3-azido-4- O -benzoyl-6-bromo-2,3,6-trideoxy-β D - ribo -hexopyranoside. Simultaneous reduction of the azido and bromo groups gave a mixture that was benzoylated to give methyl N,O -dibenzoyl-β- D -ristosaminide and then hydrolyzed to 15 hydrochloride (3-amino-2,3,6-trideoxy- D - ribo -hexopyranose hydrochloride).

High-performance liquid chromatographic determination and standardization of agmatine

In order to standardize the reversed-phase high-performance liquid chromatographic (RP-HPLC) determination of natural polyamines, particularly of agmatine, which is important in plant physiology, a simple dansylation and thin-layer chromatography (TLC) procedure was developed for the separation and purification of dansyl-agmatine. The monodansyl structure of the agmatine derivative was verified by mass spectrometry. Dansyl-agmatine was used as a reliable reference compound for the validation of an improved RP-HPLC method and to the quantitation of plant polyamines. In two varieties of wheat that had been stressed by cold treatment, significant changes were demonstrated in the agmatine content of plant seedlings.

Hydantoins, thiohydantoins, glycocyamidines—36: 1,5,5- and 3,5,5-triphenyl derivatives

Abstract In contrast to the α-chloroamides 1a-c which, when reacted with potassium N-cyanoanilide, furnish anomalous substitution products ( 2a-c ), the related nitrile and ester yields normal substitution products ( 3a and b ) under the same conditions. 1,5,5-Triphenylhydantoin ( 4a ) and a series ( 5a-8a, 13 and 14 ) of its derivatives have been prepared starting with 3a and b . Acid hydrolysis of 3a yields, in addition to the normal products ( 4a and 5a ) considerable quantities of the rearranged product 4b . An authentic sample of the latter, as well as a series of its derivatives ( 5b-8b and 11 ) have been prepared starting with α,α-diphenylglycinonitrile and 2-methylthio-1,4,4-triphenyl-2-imidazolin-5-one ( 9 ). When reacted with ammonia and ammonium iodide, 9 gave, in addition to the normal ammonolysis product 7b , the Dimroth rearrangement product 16 , as well as 5,5-diphenylglycocyamidine, by apparent dephenylation of 16 . The mass spectra of the imidazole derivatives 4–8, a and b, 9, 11, 13 and 14 are discussed.

The reaction of N-cyanoamines with 1-(t-butyl)-3,3-diphenylaziridinone: A general method for the synthesis of 1-alkyl-, 1-aralkyl- and 1-aryl-5,5-diphenylhydantoins and -glycocyamidines

Abstract N-Cyanomanines react with aziridinone 1 to yield the amides 2 . Base catalysed ring closure of the latter furnished the glycocyamidines 3 . Acid catalysed de-t-butylation, and deimination combined with de-t-butylation of the compounds 3 leads to 1-substituted 5,5-diphenylglycocyamidines ( 4 ) and -hydantoins ( 5 ), respectively. Part of the hydantoins 5 were also directly obtained by hydrochloric acid treatment of amides 2 . Selective de-t-butylation in position 3 of the glycocyamidine 3 (R = t-Bu) was brought about by heating with methanolic NH 3 in the presence of NH 4 I. Reaction of 1 with the un substituted N-cyanoamine furnished carbodiimide 7 which was cyclized to the glycocyamidine 8 . The mass spectra of some glycocyamidines 4 and hydantoins 5 , as well as of compounds 7 and 8 are discussed.

Electron impact studies on some organochlorogermanes: Mass spectra and bond dissociation energies

The mass spectra of the methylchlorogermanes and the (chloromethyl)-trichlorogermanes are described and analysed. It is shown by consideration of the ionisation and appearance potentials that the surprisingly high abundance of (MCl)+ ions in the spectrum of Cl3GeCH3 is due to a large decrease of the GeCl bond strength in the molecular ions of methylchlorogermanes with increase in the number of Cl atoms on Ge. Calculated bond energies indicate that this phenomenon reflects GeCl bond energy differences in the neutral molecules.