361479-94-9

Upstream product

• 1679-36-3 3-hexyn-2-one 
• 626-34-6 ethyl aminocrotonate 
• 41867-20-3 ethyl (E)-3-aminobut-2-enoate 
• 626-34-6 ethyl 3-aminobut-2-enoate 
• 141-97-9 ethyl acetoacetate 

Relevant academic research and scientific papers

One-pot multistep Bohlmann-Rahtz heteroannulation reactions: Synthesis of dimethyl sulfomycinamate

(Chemical Equation Presented) The synthesis of dimethyl sulfomycinamate, the acidic methanolysis product of the sulfomycin family of thiopeptide antibiotics, from methyl 2-oxo-4-(trimethylsilyl)but-3-ynoate is achieved in a 2,3,6-trisubstituted pyridine synthesis that proceeds with total regiocontrol in 13 steps by the Bohlmann-Rahtz heteroannulation of a 1-(oxazol-4-yl)enamine or in 12 steps and 9% yield by three-component cyclocondensation with N-[3-oxo-3-(oxazol-4-yl)propanoyl]serine and ammonia in ethanol.

New N-halosuccinimide-mediated reactions for the synthesis of pyridines

5-Bromo-2,6-dialkylpyridine-4-carboxylates are generated in excellent yield by the Michael addition of enaminoesters and ethynyl ketones followed by bromocyclization using N-bromosuccinimide within 1 hour at 0°C. Treatment of the same aminopentadienone intermediates with N-iodosuccinimide facilitates a low temperature cyclodehydration under very mild conditions to give 2,3,6-trisubstituted pyridines with total regiocontrol.

A new mild method for the one-pot synthesis of pyridines

Polysubstituted pyridines are prepared in good yield and with total regiocontrol by the one-pot reaction of an alkynone, 1,3-dicarbonyl compound and ammonium acetate in alcoholic solvents. This new three-component heteroannulation reaction proceeds under mild conditions in the absence of an additional acid catalyst and has been used in the synthesis of dimethyl sulfomycinamate, the acidic methanolysis degradation product of the sulfomycin family of thiopeptide antibiotics.

A new one-step synthesis of pyridines under microwave-assisted conditions

Tri- or tetrasubstituted pyridines are prepared by microwave irradiation of ethyl β-aminocrotonate and various alkynones in a single synthetic step and with total control of regiochemistry. This new one-pot Bohlmann-Rahtz procedure conducted at 170°C in a

Synthesis of tetrasubstituted pyridines by the acid-catalysed Bohlmann-Rahtz reaction

New facile experimental procedures for the preparation of 2,3,4,6-tetrasubstituted pyridines in a single synthetic step have been developed. Thus, an enamino ester and alkynone react by Michael addition-cyclodehydration in a heterocyclisation process that is catalysed by acetic acid, Amberlyst 15 ion exchange resin, zinc(II) bromide or ytterbium(III) triflate. The new one-step Bronsted or Lewis acid-catalysed Bohlmann-Rahtz reaction is a simple, direct and highly expedient method for the synthesis of pyridines that proceeds at a lower reaction temperature and avoids the need to isolate reaction intermediates.

A new one-pot three-component condensation reaction for the synthesis of 2,3,4,6-tetrasubstituted pyridines

The one-pot three-component condensation of a β-ketoester, ammonia and an alkynone in the presence of a Bronsted or Lewis acid or Amberlyst 15 ion exchange resin provided 2,3,6-trisubstituted or 2,3,4,6-tetrasubstituted pyridines directly in good yield and with total regiocontrol.

A new modification of the Bohlmann-Rahtz pyridine synthesis

A range of highly functionalised pyridines is prepared from enamino esters and alkynones in a single synthetic step by the use of acetic acid or amberlyst 15 ion exchange resin at 50°C.

Synthesis of pyridines and pyrido[2,3-d]pyrimidines by the Lewis acid catalysed Bohlmann-Rahtz heteroannulation reaction

Lewis acids catalyse the Bohlmann-Rahtz heteroannulation reaction to generate highly functionalised pyridines from enamino esters and alkynones in a single synthetic step. Of the catalysts studied, ytterbium(III) trifluoromethanesulfonate and zinc(II) bromide are the two most efficient for the synthesis of pyridines and pyrido[2,3-d]pyrimidines, from ethyl β-aminocrotonate or 2,6-di-aminopyrimidin-4-one respectively, in up to 94% yield.