Phytochemical analysis of the leaves of BOLDOA PURPURASCENS Cav. led to isolation of four flavone glycosides, three of which are new compounds. Their structures have been determined by mass ...spectrometry and by 1 D and 2 D NMR analysis, i. e., 4',5-dihydroxy-6,7-methylenedioxyflavonol 3- O-alpha- L-rhamnopyranosyl-(1-->2)-beta- D-xylopyranoside ( 1), 4',5-dihydroxy-6,7-methylenedioxyflavonol 3- O-beta- D-xylopyranoside ( 2), and 4',5-dihydroxy-6,7-methylenedioxyflavonol 3- O-alpha- L-rhamnopyranosyl-(1-->2)-beta- D-glucopyranoside ( 3). The known compound was 4',5-dihydroxy-6,7-methylenedioxyflavonol 3- O-beta- D-glucopyranoside ( 4). The aglycone 4',5-dihydroxy-6,7-methylenedioxyflavonol is known as gomphrenol. Compounds 1 and 2 failed to show antifungal activity when tested against three different strains of fungi, i. e., FUSARIUM CULMORUM, BOTRYTIS CINEREA, and ASPERGILLUS FLAVUS.
Tetrapyrrole macrocycles, of which the pyrroles are connected by sp2 centers, were readily obtained from porphyrin tetraphenols by air oxidation under basic conditions, followed by
N-alkylation. The ...degree of
N-alkylation could be controlled and either di- or tetraalkylated derivatives are obtained in high yields.
Graphic
The synthesis of 1,5-anhydrohexitol nucleosides is described. These nucleoside analogues were obtained by alkylation of the heterocyclic bases with the tosylate 10 or by alkylation of the bases with ...the alcohol 12 under Mitsunobu conditions. The compounds were evaluated for antiviral and cytostatic activity. Highly selective activity against herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) was noted for 1,5-anhydro-2,3-dideoxy-2-(5-iodouracil-1-yl)-D-arabino-hexitol 4b at a concentration of 0.07 microgram/mL. This activity must be dependent on a specific phosphorylation by the virus-encoded thymidine kinase (TK), since compound 4b was inactive against TK-deficient mutants of HSV-1. The corresponding cytosine 4c and guanine 4e analogues showed activity against HSV-1, HSV-2, and other herpes viruses (i.e. cytomegalovirus, varicella-zoster virus) at concentrations well below the cytotoxicity threshold (2 and 20 micrograms/mL, respectively). At these concentrations, compounds 4c and 4e proved also inhibitory to the growth of human T-cells (i.e. MT-4, CEM, MOLT-4).
Graphic
Reaction of 2-hydrazinothiazoles
1 with 1-thienyl- and 1-furyl-1,3-butanediones
2a,
b in methanol in the presence of hydrochloric acid mainly leads to a mixture of pyrazoles
3 and pyrazolines
...4 or pyrazoles
3 and
5 in strong acidic conditions. Isomeric hydrazones
6 and pyrazolines
4 were formed and isolated in these reactions in the absence of hydrochloric acid. It has been shown that the regioselectivity in the reaction of diketones
2 with hydrazine
1 is governed by both the concentration of acid and the nature of substituents in the 1,3-diketones
2. Cyclization of hydrazones
6 is shown to occur under milder conditions than dehydration for pyrazolines
4. The new heterocyclic compounds were prepared and fully characterized by NMR spectra and by X-ray analysis for
3c.
A systematic study of the reactions of dimethyl acetylenedicarboxylate (DMAD) and methyl propynoate with 5-mercaptoazoles and pyridine-2-thiones has been carried out and as a result, a number of ...novel imidazo1,5-bthiazin-4-ones 6a,b, pyrazolo1,5-b thiazin-4-ones 15a-f, imidazo1,5-bthiazol-4-ones 7a,b and thiazolo3,2-apyridines 21a-c have been prepared. The influence of the size of the ring of the starting "cyclic" thioamides on the size of the fused ring in the reaction products has been established. The preferred formation of a six-membered thiazine ring took place in the reactions of 5-mercaptoazoles. In contrast, the five membered thiazolidine ring is formed in reactions of pyridine-2-thiones. In both cases the product is a five-membered ring fused to a six-membered heterocycle.
1-Amino-1-deoxy-
d-glucitol (
14) was converted to the
N-Boc-2,3;5,6-di-
O-isopropylidene derivative
16 which was transformed further into the selectively protected 2,3-
O-isopropylidene 6-azido ...piperidine
3. The synthesis proceeded via a double inversion at C-5 involving internal attack of 4-OH to form the 4,5-epoxide
28, and ring opening of this epoxide by 1-NH
2 to generate the piperidine
3. This served as a valuable precursor of various target compounds, i.e. 6-azido- and 6-amino-1,6-dideoxynojirimycin
4 and
5, and the mono- and bicyclic derivatives
6–
12.
