Synthesis of Pyrrolo[2,3-d][1,2,3]thiadiazole-6-carboxylates via the Hurd-Mori Reaction. Investigating the Effect of the N-Protecting Group on the Cyclization
Synthesis of Pyrrolo[2,3-d][1,2,3]thiadiazole-6-carboxylates via the Hurd-Mori Reaction. Investigating the Effect of the N-Protecting Group on the Cyclization
作者:P, Stanetty、M. Turner、M. Mihovilovic
DOI:10.3390/10020367
日期:——
A route to methyl pyrrolo[2,3-d][1,2,3]thiadiazole-6-carboxylates as potential plant activators and inducers of systemic acquired resistance (SAR) is reported. A synthetic strategy based on cyclization of the thiadiazole ring system utilizing thionyl chloride via the Hurd-Mori protocol as key step was developed. Success of the ring closure reaction turned out to be highly dependent on the nature of the N-protecting group of the pyrrolidine precursor. While electron donors such as alkyl gave only poor conversion to the required 1,2,3-thiadiazoles, an electron withdrawing substituent such as methyl carbamate gave superior yields.
Hetero-1,3-dipolar cycloadditions of dithiolane-isocyanate imminium methylides: A novel route to 1,3-oxazolidine- and thiazolidine-2-thiones
作者:Colin W.G. Fishwick、Richard J. Foster、Robin E. Carr
DOI:10.1016/0040-4039(95)02249-x
日期:1996.1
Dithiolane- isocyanate imminium methylides which are a new type of azomethine methylide-derived 1,3-dipole undergo efficient and regioselective cycloaddition to conjugated carbonyls and thiocarbonyls to yield predominantly 1,3-oxazolidine- and thiazolidine-2-thiones formed from the initial cycloadducts via loss of thurane.
A convenient and new approach to the synthesis of ω-heterocyclic amino acids from carboxy lactams through ring-chain-transformation. Part 2: Synthesis of (2R)-/(2S)-2-aminomethyl-3-(1-aryl-/1,5-diaryl-1H-pyrazol-3-yl)-propionic acid
作者:Rakesh K. Singh、Neelima Sinha、Sanjay Jain、Mohammad Salman、Fehmida Naqvi、Nitya Anand
DOI:10.1016/j.tet.2005.07.018
日期:2005.9
and short path synthesis of optically pure ω-heterocyclic-β-amino acids has been achieved from (1R,3R)- and (1R,3S)-5-oxo-1-(1-phenyl-ethyl)-pyrrolidine-3-carboxylic acid methyl ester. The key step of the synthesis involves a regiospecific ring-chain-transformation of the enaminones when subjected to 1,2-binucleophilic attacks. The method is illustrated by the synthesis of (2R)-/(2S)-2-aminomethyl-3-(1-aryl-/1
A general and efficient synthesis of 3,6-diazabicyclo[3.2.1]octanes
作者:Rakesh K. Singh、Sanjay Jain、Neelima Sinha、Anita Mehta、Fehmida Naqvi、Nitya Anand
DOI:10.1016/j.tet.2006.02.030
日期:2006.4
A convenient and efficient synthesis of N6-substituted 3,6-diazabicyclo[3.2.1]octanes (6a–c) has been achieved starting from suitably substituted lactams, which were converted to nitroenamines followed by reductive cyclization to afford 3,6-diazabicyclo[3.2.1]octane-2-ones in good yields. These bicyclic lactams were then reduced to the corresponding 3,6-diazabicyclo[3.2.1]octanes and converted to the
N 6取代的3,6-二氮杂双环[3.2.1]辛烷(6a – c)的合成方便高效,从适当取代的内酰胺开始,将其转化为亚硝胺,然后进行还原环化,得到3,6-重氮二氮杂双环[3.2.1]辛烷-2-酮。然后将这些双环内酰胺还原为相应的3,6-二氮杂双环[3.2.1]辛烷,并转化为所需的N 3,N 6-双取代的3,6-二氮杂双环[3.2.1]辛烷(7a – h),筛选α 1 -肾上腺素受体拮抗活性。