623 J. Indian Chem. Soc., Vol. 95, June 2018, pp. 623-627 Synthesis of a series of aldol compounds by direct LDA reaction from pyruvaldehyde dimethyl acetal and 3-arylmethylidine pentane-2,4-diones by Knoevenagel reaction Shampa Chakraborty a,b , Shyamaprosad Goswami* b and Ching Kheng Quah c a Waste Water Technology Division, National Engineering Research Institute, Nagpur-440 020, Maharashtra, India E- mail: sh.chakraborty@neeri.res.in b Department of Chemistry, Indian Institute of Engineering Science & Technology, Shibpur, Howrah-711 103, West Bengal, India E- mail: spgoswamical@yahoo.com c X-Ray Crystallography Unit, School of Physics, Universiti Sains Malaysia, 11800 USM, Penang, Malaysia E- mail: ckquah@usm.my Manuscript received 22 March 2018, revised 11 April 2018, accepted 08 May 2018 A new convenient synthesis of aldol compounds starting from pyruvaldehyde dimethyl acetal has been described. This method conveniently led to the synthesis of some biologically important compounds 1,2 . A new synthesis of 3-arylmethylidine pentane- 2,4-diones is reported via usual Knoevenagel condensation which has a significant role in synthesizing different sensors for metal cations or anions. Keywords: Benzazoles, azoles, single step reaction, room temperature reaction, sensor application. Introduction There are many reports for the study of the aldol reaction of pyruvaldehyde dimethyl acetal by organocatalyzed enantioselective enamine type reactions 1–8 . PEP (Phospho- enolpyruvate) and aldolase mimicry are essential for a direct organocatalytic entry for biomolecules of huge importance in chemical, biological and medicinal fields. In the key aldol reaction, the dimethyl acetal of pyruvic aldehyde is used as phosphoenolpyruvate (PEP) equivalent. In this communica- tion, we report our results of an investigation of the same reaction under LDA reaction condition. In this manuscript, we have reported the synthesis of the aldol products (1a-1c) from pyruvaldehyde dimethyl acetal with benzaldehyde, 3-pyridylaldehyde, 2-nitrobenzaldehyde in LDA. The yield of the reaction is low because of the forma- tion of the unsaturated analogue of the products in such a strong basic condition (Scheme 1). We have also synthe- sized the products 2a-2f by Knoevenagel reaction conditions. The product molecules have the biological activity in both cases, 2a-2f can act as good precursors for the active sen- sor molecules for transition metals. These compounds can be further converted into new heterocyclic compounds, or they (1a-1c or 2a-2f) can be functionalized more to synthe- size new receptor molecules for recognition studies. Results and discussion In recent years many useful chemical and enzymatic methodologies have been reported and implemented to de- velop efficient synthesis of desired aldol products as well as of certain analogs 9,10 . However, in enzyme-catalyzed reac- Scheme 1. Aldol reaction of pyruvaldehyde dimethyl acetal with dif- ferent aldehydes for the synthesis of compounds (1a-1c). a Current address. JICS-6