Notes 2-Chloromethyl-5-hydroxy-4-pyrone (3), mp 165-166 °C (lit.30 mp 166-167 °C).2-Hydroxymethyl-5-methoxy-4-pyrone (5), mp 119-120 °C (lit.31 mp 119-121 °C).2-Acetoxymethyl-5-aCetoxy-4-pyrone (6). This material was prepared by acetylation of kojic acid, mp 100-102 °C (lit.32 mp 102 °C).Comenic Acid (7). This.compound was prepared by catalytic oxidation pf kojic acid, mp 220 °C dec (lit.33 mp not specified).Hydroxymaltol (2-hydroxymethyl-3-hydroxy-4-pyrone) (9), mp 149-151 °C (lit.34 mp 152-153 °C).

No abstract

(‐)‐3‐Kthylpiperidine and (R)‐(‐)‐2‐ethylglutarie acid have been chemically correlated through N‐subslituted α‐ethylglutarimides obtained from the oxidation of optically active N‐ethyl‐ and N‐benzyl‐3‐ethylpiperidine with ruthenium tetroxide. The (R)‐(‐) configuration of (‐)‐3‐ethylpiperidine was confirmed by CD measurements. The selective oxidation of endocyclic methylenes linked to the nitrogen atom was explained in term of different conformational freedom of endo‐ and exocyclic methylene groups.

2‐Amino‐thiophenol (I) reagiert mit den Acetylenen (II) zu den Benzothiazinen (III), deren Reduktion mit Natriumborhydrid/Essigsäure zu Gemischen der Dihydrobenzothiazine (IV)‐(VI) führt.

Acid catalyzed cyclization reactions of both 3‐alkyl‐ and 3‐aryl‐substituted N‐/2,2‐dialkoxyethyl)‐3,4‐dihydro‐2H‐1,4‐benzothiazines (2) lead to 2,3‐dihydro‐pyrrolo[1,2,3‐de]‐1,4‐benzothiazines (3). The pyrrolobenzothiazine structure was deduced on the basis of 2D 1H NMR‐NOESY experiments and fully determined by X‐ray data. Compounds 3a‐c showed poor antibacterial activity. However, the 3‐phenyl‐N‐(2,2‐dimethoxyethyl)‐3,4‐dihydro‐2H‐1,4‐benzothiazine (2b′) showed antifungal activity against Aspergillus niger 16‐fold greater than miconazole.