Glowczyk, Joanna et al. published their research in Roczniki Chemii in 1977 | CAS: 10203-58-4

Diethyl isobutylmalonate (cas: 10203-58-4) belongs to esters. Volatile esters with characteristic odours are used in synthetic flavours, perfumes, and cosmetics. Certain volatile esters are used as solvents for lacquers, paints, and varnishes. Cyclic esters are called lactones, regardless of whether they are derived from an organic or inorganic acid. One example of an organic lactone is γ-valerolactone.Product Details of 10203-58-4

Reaction of alkyl malonates with nitric acid was written by Glowczyk, Joanna;Lange, Jerzy;Abramski, Jan W.. And the article was included in Roczniki Chemii in 1977.Product Details of 10203-58-4 This article mentions the following:

The title reaction with fuming HNO3 gave RC(NO2)(CO2Et)2 (I; R = Me, Et, Me2CH, Bu, Me2CHCH2, Me3C) and RC(OH)(CO2Et)2 (II); the ratio I–II depended on the temperature At low temperature II was favored and at high temperature I was favored. The degree of conversion depended on R. In the experiment, the researchers used many compounds, for example, Diethyl isobutylmalonate (cas: 10203-58-4Product Details of 10203-58-4).

Diethyl isobutylmalonate (cas: 10203-58-4) belongs to esters. Volatile esters with characteristic odours are used in synthetic flavours, perfumes, and cosmetics. Certain volatile esters are used as solvents for lacquers, paints, and varnishes. Cyclic esters are called lactones, regardless of whether they are derived from an organic or inorganic acid. One example of an organic lactone is γ-valerolactone.Product Details of 10203-58-4

Referemce:
Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics