A new solvent-free method for synthesis of starting compounds 2,4-dioxochromen-3(4
H)methyl amino acetic acid derivatives
1a–
e via a green approach is reported. Also, the behavior of compound
1a towards various nitrogen nucleophiles such as primary amines, hydrazine hydrate, and hydroxylamine hydrochloride to give corresponding compounds
2–
4 was studied. Furthermore, chlorination of compound
1a using a mixture of PCl
5/POCl
3 to yield acid chloride derivative
5 and the reaction of the latter compound
5 with various amino acids to obtain dipeptide compounds
6a–
e are described. Moreover, cyclization of compound
1a in alkaline medium to afford dihydrochromeno[3,4-
c]pyrrole-1-carboxylic acid
7 and cyclization of
6b in acidic medium, namely Ac
2O, to yield piperazine derivative
8 are reported. Also, reaction of compound
1a with maleic anhydride in dioxane to afford Diels–Alder adduct
9, which posteriorly reacted with hydrazine hydrate to give
10, was investigated. Most of the newly synthesized compounds were screened against Gram-positive and Gram-negative bacteria, with compound
5 exhibiting the maximum inhibition zone towards all four types of bacteria. In addition, the absorption and fluorescence emission of some of the substituted coumarins were studied in dioxane, revealing that the substituents altered both the absorption and fluorescence emission maxima.
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