a b s t r a c tWe describe a one-pot four component synthesis of pyranopyroles from aryl aldehydes, ethyl acetoacetate, malononitrile and hydrazine hydrate in the presence of catalytic amounts of an organocatalyst imidazole in water as medium. A plausible mechanism for the formation of imidazole catalyzed pyranopyrazoles has been envisaged. This method is rapid, simple, provides products in good yield, and is eco-friendly. In addition, based on the optimized geometry, the frequency and intensity of the vibrational bands of 6-amino-4-(4 -methoxyphenyl)-5-cyano-3-methyl-1-phenyl-1,4-dihydropyrano[2,3-c]pyrazole were obtained by the density functional theory (DFT) calculations using 6-31G(d,p) basis set. The vibrational frequencies were calculated and the scaled values have been compared with experimental FT-IR and FT-Raman spectra. The observed and the calculated frequencies are found to be in good agreement.

a b s t r a c tSonochemical oxidation of benzyl alcohols into corresponding aldehydes by FeCl 3 /HNO 3 in acetone at room temperature has been reported. All substrates give good yield of the products within 10-25 min. The reaction of selected substrates were also studied under reflux and at the room temperature. Further, various Lewis acids were used to evaluate their catalytic efficacy.

ZnO has been shown to be an inexpensive, efficient, readily available, and mild catalyst for a one-pot fourcomponent synthesis of some novel octahydroquinolindione-3-carboxylic acid ethyl esters using diethylmalonate, dimedone, ammonium acetate, and appropriate aromatic aldehydes in water at reflux. ZnO acts as a recyclable heterogeneous catalyst to afford the products in excellent yield in short reaction duration.

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Objectives:  A series of new dihydropyrano [2,3-c]pyrazol-6-amines in this investigation  study, are synthesized  by the strategy of one-pot four component reaction in an aqueous medium. Methods:  After getting optimum conditions the reaction of different substituted aromatic aldehydes, ethyl acetoacetate, hydrazine hydrate,  and phenylacetonitrile catalysed by Sodium hydrogen sulphate NaHSO4 (0.5 m mol) by refluxing in ethanol-water (1:1) (5 ml) and heated at 80 oC. The synthesized molecules product was filtered, washed with water to get nearly pure product in excellent yield. Results:  The pure products which were got in a short duration, with excellent yield (80 – 87%). Those new compounds were identified by using spectroscopic techniques FT-IR, 1H-NMR and 13C-NMR. Conclusion: In conclusion, the usefulness of this one-pot multicomponents protocol include easily available starting materials, facile, simple and environment-friendly procedure, and easier separation of products by filtration. Peer Review History: Received 5 March 2019; Revised 11 April; Accepted 9 May, Available online 15 May 2020 UJPR follows the most transparent and toughest ‘Advanced OPEN peer review’ system. The identity of the authors and, reviewers will be known to each other. This transparent process will help to eradicate any possible malicious/purposeful interference by any person (publishing staff, reviewer, editor, author, etc) during peer review. As a result of this unique system, all reviewers will get their due recognition and respect, once their names are published in the papers. We expect that, by publishing peer review reports with published papers, will be helpful to many authors for drafting their article according to the specifications. Auhors will remove any error of their article and they will improve their article(s) according to the previous reports displayed with published article(s). The main purpose of it is ‘to improve the quality of a candidate manuscript’. Our reviewers check the ‘strength and weakness of a manuscript honestly’. There will increase in the perfection, and transparency. Received file Average Peer review marks at initial stage: 5.0/10 Average Peer review marks at publication stage: 7.0/10 Reviewer(s) detail: Name: Prof Cyprian Ogbonna ONYEJI Affiliation: Obafemi Awolowo University, Ile-Ife, Nigeria E-mail: conyeji@oauife.edu.ng   Name: Dr. Md. Shahidul Islam Affiliation: USTC, Chittagong, Bangladesh E-mail: S_i_liton@yahoo.com Comments of reviewer(s): Similar Articles: TOXICITY AND ANTITRYPANOSOMAN ACTIVITY OF HEMI SYNTHESIS PRODUCTS OBTAINED FROM BIOACTIVE COMPOUNDS OF MITRACARPUS SCABER HARVESTED SOUTH OF BENIN