A compound A has prominent infrared absorptions at 1050, 1786, and 1852 cm–1 and shows a single absorption in the proton NMR spectrum at δ 3.00. When heated gently with methanol, compound B, C5H8O4, is obtained. Compound B has IR absorptions at 2500–3000 (broad), 1730, and 1701 cm–1, and its proton NMR spectrum in D2O consists of resonances at δ 2.7 (complex splitting) and δ 3.7 (a singlet) in the intensity ratio 4:3. Give the structures A and B, omitting stereochemistry.

Compound A is succinic anhydride and B is methyl succinate (the monomethyl ester).

Structural Diagram is attached.

Explanation:

A.

Succinic anhydride appears as colorless needles or white crystalline solid. ... Succinic anhydride, also called dihydro-2, 5-furandione, is an organic compound with the molecular formula C4H4O3. It is the acid anhydride of succinic acid.

B.

Monomethyl succinate is a dicarboxylic acid monoester that is succinic acid in which one of the carboxy groups has been converted to its methyl ester. It is a dicarboxylic acid monoester and a hemisuccinate. ... They have the general structure RC(=O)OR', where R=fatty aliphatic tail or organyl group and R'=methyl group.

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