Abstract:1. Einleitung. -Die Chemie der 2H-Azirine ist eingehend untersucht und in zahlreichen Arbeiten beschrieben worden (obersichtsartikel [ 1-41; fur neuere Arbeiten siehe [5-121 und dort zit. Lit.). Die leichte Zuganglichkeit dieses gespannten Stickstoffdreiringes (vgl. z. B. [ 13-16]), sowie die Moglichkeit, unter geeigneten Reaktionsbedingungen jede der drei Ringbindungen selektiv zu spalten, machen 2 H-Azirine zu wertvollen Synthesebausteinen fur N-haltige Verbindungen. Theoretische Untersuchungen [ 171 sowie R… Show more
“…the synthesis of 2H-azirin-3-amines 1 [35], used by Strässler for the preparation of 1b (n = 1) [12], is limited to N-alkyl-N-phenyl derivatives, we decided to prepare N- (9), with the aim of following the protocol of the aminoazirine synthesis published by Rens and Ghosez [36] and modified by Dietliker [37]. Thus, tetrahydro-2H-thiopyran-4-carboxylic acid chloride (6) [12] was reacted with L-proline methyl ester (7) to give N-[(tetrahydro-2H-thiopyran-4-yl)carbonyl]-L-proline methyl ester (8) in 85% yield, which was converted to 9 by thionation with Lawesson reagent in 67% yield (Scheme 2).…”
Section: Synthesis Of the Heterospirocyclic Azirine 1c As The Methodmentioning
Starting with tetrahydro-2H-thiopyran-4-carboxylic acid and methyl prolinate, the novel 2H-azirin-3-amine (S)-N-(1-aza-6-thiaspiro[2.5]oct-1-en-2-yl)proline methyl ester was synthesized. In reactions with benzoic acid, thiobenzoic acid and Boc-valine, respectively, its usefulness as a synthon for the dipeptide (S)-N-[(4-aminotetrahydro-2H-thiopyran-4-yl)carbonyl]proline in peptide synthesis was demonstrated.
“…the synthesis of 2H-azirin-3-amines 1 [35], used by Strässler for the preparation of 1b (n = 1) [12], is limited to N-alkyl-N-phenyl derivatives, we decided to prepare N- (9), with the aim of following the protocol of the aminoazirine synthesis published by Rens and Ghosez [36] and modified by Dietliker [37]. Thus, tetrahydro-2H-thiopyran-4-carboxylic acid chloride (6) [12] was reacted with L-proline methyl ester (7) to give N-[(tetrahydro-2H-thiopyran-4-yl)carbonyl]-L-proline methyl ester (8) in 85% yield, which was converted to 9 by thionation with Lawesson reagent in 67% yield (Scheme 2).…”
Section: Synthesis Of the Heterospirocyclic Azirine 1c As The Methodmentioning
Starting with tetrahydro-2H-thiopyran-4-carboxylic acid and methyl prolinate, the novel 2H-azirin-3-amine (S)-N-(1-aza-6-thiaspiro[2.5]oct-1-en-2-yl)proline methyl ester was synthesized. In reactions with benzoic acid, thiobenzoic acid and Boc-valine, respectively, its usefulness as a synthon for the dipeptide (S)-N-[(4-aminotetrahydro-2H-thiopyran-4-yl)carbonyl]proline in peptide synthesis was demonstrated.
“…durch Photolyse von 3-(N-Methylanilino)-2H-azirinen i erzeugt worden [8]. Auch die Umsetzung von 6e mit dem 1,3-Thiazol-S(4H)-thion 12 ergab ein Gemisch zweier stereoisomerer Cycloaddukte, namlich 18a und 18b (Schema 7), die mittels…”
Section: ')unclassified
“…S. [8] Dimethyl-5,-(benzylthio jspiro[cyclohexun-l.2'-[3,4]dihydro-2'H-pyrrol]-3',4'-dicarboxylut (9). Eine Lsg.…”
Thermal Generation and Reactions of (Benzy1thio)-and (Ary1thio)-Substituted Nitrile YlidesThermolysis of 4-(benzy1thio)-and 4-(ary1thio)-1,3-oxazol-5(2H)-ones 6, at 1 10-1 55" in the presence of dipolarophiles with activated CEC, C=C, C=O, C=S, and N=N bonds, led to 5-membered cyclo-adducts and C 0 2 (el: Schemes 3, 5-7). Heating 6a and 6c in the presence of ethyl propiolate yielded ethyl quinoline-3-carboxylate (19) and ethyl pyridine-3-carboxylate (22), respectively (cf. Scheme 8 ) . These results are rationalized on the basis of the intermediate formation of thio-substituted nitrile ylides of type 7 (cf. Scheme 2 ) , which undergo regioselective 1,3-dipolar cycloadditions with reactive dipolarophiles. In the absence of such a dipolarophile, the nitrile ylides isomerize uia a [1,4]-H shift to give 2-aza-1,3-butadienes of type 20. The latter are trapped in a Diels-Alder reaction with ethyl propiolate (cf. Scheme 8).
Synthesis of 4,4-Disuhstituted 1,3-Thiazol-5(4H)-thionesAn easy synthesis for the 1,3-thiazol-5(4H)-thiones 5, a class of heterocycles which have hitherto only been available with difficulty, is described. Reaction of 3-amino-2H-azirines 25 with thiocarboxylic acids at 0" yields rnonothiodiamides oftype 20 (Scheme 6 ) which, on treatment with Lowsson reagent at loo", undergo thiation and cyclization to give 5 in good yield.
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