Umsetzung von vinylogen Formamidiniumsalzen mit Nucleophilen, II. Polymethiniumsalze aus methylenaktiven Ketonen

Abstract

Methylenaktive Ketone 2 kondensieren mit den vinylogen Amidacetalen und Aminalestern 1 a, b oder rnit den vinylogen hmidiniumsalzen 8 und Natriummethylat zu substituierten 5-(Dimethylamino)pentadienonen 3a-m, 4a, Sa-d und 6a-c, entsprechend rnit 9 zu Heptatrienonen 10af. Erhitzen von 10a-f fiihrt unter RingschluB und Dimethylaminabspaltung zu den Phenylketonen 14a-f. Die Kinetik der elektrocyclischen Reaktion von 10a zu 14a wurde gemessen. Aus den Verbindungen 3a-m, 4a, 5a-b, 6a gewonnene Polymethiniumsalze 22a-m, 23a-25b und 27 werden rnit Ammoniakl Ammoniumchlorid oder in einer Ammonacetatschmelze zu den Pyridinen 29a-m, 30a-32b und 33 cyclisiert. Aus 33 kann das neue Pseudoazulen 35 gewonnen werden. Reaction of Vinylogous Formamidinium Salts with Nucleophiles, 11. -Polymethinium Salts from Methylene-Active KetonesThe rnethylene-active ketones 2 condense with the vinylogous amide acetales and aminal esters 1 a, b or with the vinylogous amidinium salts 8 in the presence of sodium methoxide to give substituted 5-(dimethy1amino)pentadienones 3a-m, 4a, 5ad and 6a-c ; analogously, condensation with 9 affords the heptatrienones 10a-f. Heating of 1Oa-f leads, via ring closure and elimination of dimethylamine, to the phenyl ketones 14a-f. Rates and kinetics for the electrocyclic transformation of 10a into 14a were measured. The polymethinium salts 22a-m, 23a-2Sb and 27 formed from compounds 3a-m, 4a, 5a-b and 6a cyclize on treatment with ammonia/ammonium chloride or with molten ammonium acetate to the pyridines 29a--m, 30a-32b and 33. The new pseudoazulene 35 can be prepared from 33.In einer vorhergehenden Mitteilungl) haben wir gezeigt, daB vinyloge Formamidiniumsalze 8 Ausgangsverbindungen zur Synthese von Pyrimidinen sind In der vorliegenden Arbeit wird ein einfacher Weg zu neuartigen, meist hochsubstituierten Polymethiniumsalzen, Polyenonen und deren Folgereaktionen beschrieben 2). *) Korrespondenz bitte an diesen Autor richten.

Efficient Routes to Acenaphthylene‐Fused Polycyclic Arenes/Heteroarenes and Heterocyclic Fluoranthene Analogues

“…The adducts 17a-b were transformed into the corresponding 10-(methylthio)-8-arylacenaphtho[1,2-b]pyridines 18a and 18b on heating with ammonium acetate/acetic acid, in 80 % and 85 % yields, respectively. One of the products (18a) was converted into the sulfur-free acenaphthopyridine 19a [19] on treatment with Raney Ni under standard reaction conditions (Scheme 6). Scheme 6. Interestingly, this pyridine annulation strategy could also be elaborated for the synthesis of bis(acenaphtho)-annulated pyridine derivatives 21 and 22, as shown in Scheme 7.…”

Reactions at the nitrogen atoms in azafluorene systems

“…There are only a few reported examples of NAdopting the procedure reported by Hamada and alkylation of azafluorenes and azafluorenones (5)(6)(7)(8). Takeuchi (12) and oxidizing the studied compounds The N-oxidation of this class of compounds has been with H 2 0 2 in the presence of Na2W0, we obtained reported only for the cases of Cazafluorene to 2,s-diazafluorenone 2,5-dioxide 12 (30%), 4,5-di-4-azafluorene N-oxide (9) and of 3-methyl-2-aza-azafluorenone 4-oxide 15 (22%), as well as 1,5-fluorene to 3-methyl-2-azafluorene N-oxide (10).…”

Connecting a carbonyl and a π-conjugated group through a p-phenylene linker by (5+1) benzene ring formation

“…In relation to the approach, conversion of an acetyl group into an unsubstituted benzoyl group using a conjugated methine compound (streptocyanine) as a C5 source was reported by Jutz. 20 However, the mere formation of an unsubstituted phenyl group, which restricted applicability of this reaction, has not been applied to connecting two fragments through the benzene ring formed. We report here a new method for connecting a carbonyl and a p-conjugated group through a p-phenylene linker by benzene ring formation using a methyl ketone as the C1 source and a streptocyanine bearing a p-conjugated substituent as the C5 source (eqn (1)).…”

“…We first optimized the reaction conditions for the (5+1) annulation using streptocyanines bearing no internal substituent (Table 1). 20 Acetophenone (1a), streptocyanine 2, and KO t Bu were mixed and stirred in THF at 80 1C for 10 h in a pressure tube to give benzophenone (6a) in a 30% yield (entry 1). Higher reaction temperatures increased the yield of the product (entries 2 and 3).…”