Alternate, Easy and practical synthesis of allyl amines from acetyl derivatives of Baylis-Hillman adducts using Methanolic Ammonia

A methanolic ammonia-mediated alternate, easy and practical stereoselective synthesis of allyl amines from the acetyl derivatives of Baylis-Hillman adducts is described.

A reinvestigation into the reaction of NH4OAc with acetyl derivatives of Bay-lis-Hillman adducts: Formation of tertiary and secondary allyl amines in-stead of primary allyl amines

A reinvestigation into the reaction between ammonium acetate and the acetyl derivatives of Baylis-Hillman adducts has led us to conclude that the products obtained are tertiary and secondary allyl amines and not the primary allyl amines. The unambiguous assignment of the structure of products using chemical and spectroscopic methods is described

Convenient synthesis of substituted α-methylene--valerolactones in aqueous medium using Baylis-Hillman chemistry

A mild and convenient synthesis of substituted α-methylene--valerolactones was achieved by SN2 nucleophilic substitution of the acetates of the Baylis-Hillman adducts with acetyl acetone followed by one-pot saponification of the ester, reduction of the keto group and subsequent intramolecular ring closure in aqueous medium.

Trifluoroacetic acid: A more effective and efficient reagent for the synthesis of 3-arylmethylene-3,4-dihydro-1H-quinolin-2-ones and 3-arylmethyl-2-amino quinolines from Baylis-Hillman derivatives via Claisen rearrangement

Trifluoroacetic acid has been discovered to be a highly effective and efficient reagent for the tandem Claisen rearrangement and cyclisation reaction to yield 3-arylmethylene-3,4-dihydro-1H-quinolin-2-ones from compounds obtained from the SN2 reaction between anilines and acetyl derivatives of Baylis-Hillman adducts of acrylates in the presence of DABCO. In contrast similar compounds obtained from the acetyl derivatives of Baylis-Hillman adduct of acrylonitrile on treatment with trifluoroacetic acid directly furnish 3-arylmethyl-2-amino-quinoline via tandem Claisen rearrangement, cylisation and isomerisation.

Synthesis of substituted 1H- and 3H-1-benzazepines: Rearrangement of 2-alkoxycarbonyl-1H-1-benzazepines to isoquinolines

The SnCl2-mediated reduction of nitro groups in 2-nitro-4-(2-nitro-benzylidene)-alkanoates and 4-nitro-2-(2-nitro-alkylidene)-alkanoates afforded via SN2′ reaction of ethyl nitroacetate and nitroethane with the acetyl derivatives of Baylis-Hillman adducts afforded by 2-nitro-substituted benzaldehydes leads to facile synthesis of substituted 1H-1-benzazepine and 3H-1-benzazepine. During the study an unprecedented rearrangement of 2-alkoxycarbonyl-1H-benzazepine to substituted isoquinoline has been observed.

An alternate approach to quinoline architecture via Baylis-Hillman chemistry: SnCl2-mediated tandem reaction toward synthesis of 4-(substituted vinyl)-quinolines

An alternate approach to densely substituted quinolines from the products of SN2 nucleophilic substitution reaction between the acetyl derivatives of the Baylis-Hillman adducts obtained from 2-nitrobenzaldehydes and the carbonyl group containing carbon nucleophiles is described. Treatment of these compounds with SnCl2, trigger a tandem reaction wherein reduction of the nitro group is followed by a remarkably regioselective intramolecular cyclization and subsequent dehydrogenation to afford 4-(substituted vinyl)-quinolines.

Significant yield improvement in the stereoselective synthesis of allyl cyanides from Baylis-Hillman derivatives in aqueous medium under the influence of the Phase-Transfer catalyst

The nucleophilic reaction of NaCN with the acetyl derivative of Baylis-Hillman adducts in the presence of a phase-transfer catalyst in aqueous medium stereoselectively affords the corresponding allyl cyanides in a short period and excellent yields.

Application of primary allyl amines afforded by the Baylis-Hillman adducts for heterocyclic synthesis: Generation of 5-benzyl-4(3H)-pyrimidinones and 2-benzylidene-2,3-dihydro-pyrrolizin-1-ones

The applications of the primary allyl amines afforded by the acetyl derivative of Baylis-Hillman adducts of acrylate for the synthesis of heterocycles using robust reactions are described. In the first strategy a one-pot synthesis of 5-benzyl-4(3H)-pyrimidinones have been achieved via N-formylation of the amines in the presence of neat formamide followed by ammonium formate-mediated cyclization. These pyrimidinones have been demonstrated to be excellent precursor to the 4-pyridinamine derivatives. In the second strategy the synthesis of 2-benzylidene-2,3-dihydro-pyrrolizin-1-ones have been accomplished via treatment of allyl amine with dimethoxyfuran followed by saponification and PPA-mediated intramolecular cyclization.