Preparation of CH‐diazomethane sulfonamides has been developed for the first time. Their utility as a new type of diazo reagents was showcased in cycloaddition reactions with electron‐deficient alkynes and β‐nitro styrenes which delivered medicinally important pyrazole‐3‐sulfonamides in good to excellent yields.
A new
type of diazo compounds, namely, CH-diazomethane sulfonamides
(generated in situ from readily available α-acetyl-α-diazomethane
sulfonamides), was employed in a 1,3-dipolar cycloaddition reaction
with imines (also formed in situ from primary amines
and aldehydes). The reaction gave hitherto undescribed 1,5-disubstituted
1,2,3-triazoline-4-sulfonamides, which were obtained in good to excellent
yields with complete trans diastereoselectivity. These new sulfonamides
based on the nonaromatic 1,2,3-triazoline core are rather attractive
from a medicinal chemistry standpoint in light of the strong emphasis
recently put on the nonflat, more saturated (higher Fsp3) scaffolds
for lead-generation libraries. The oxidative aromatization of 1,2,3-triazoline-4-sulfonamides
by manganese(IV) oxide gave nearly quantitative yields of 1,2,3-triazole-4-sulfonamides,
of which only two examples have been reported in the literature.
A three-component
synthesis of 1,5-disubstituted 1,2,3-triazoles
from α-acetyl-α-diazomethane sulfonamides, primary aliphatic
amines, and aromatic aldehydes is presented. The 1,2,3-triazoles can
be accessed in two alternative variants, depending on the substitutions
in the sulfonamide portion of the diazo reagent. In one variant, intermediate
1,2,3-triazoline-4-sulfonamides are isolated chromatographically and
then subjected to thermally promoted aromatization with elimination
of sulfur(IV) oxide and amine. In the other variant, both chemical
transformations take place in a single step conducted at room temperature.
The scope of silver nitrate‐catalyzed cycloaddition of arenediazonium salts has been expanded to include aryl‐ and alkylsulfonyl diazomethanes as well as the recently introduced diazomethyl sulfonamides. The reliance on these two classes of diazo compounds led to a new synthetic approach to the rare 2‐aryltetrazol‐5‐yl sulfones as well as to the synthesis of hitherto not described 2‐aryltetrazol‐5‐yl sulfonamides.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.