{'fraction_non_alphanumeric': 0.024214322514167955, 'fraction_numerical': 0.00463678516228748, 'mean_word_length': 5.79020979020979, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Synthesis of 1,3-Oxazine-4-thione Derivatives through an Efficient, Rapid and Green Method Catalyzed by L-Proline in Aqueous Medium

The development of environmentally friendly and economical methods for the synthesis of biologically active heterocycles using readily available reagents remains a significant challenge in organic synthesis. In this context, organocatalysis has emerged as a powerful methodology in organic synthesis for the preparation of both simple and complex bioactive heterocycles Organocatalysts offer improved stability, lack of sensitivity to moisture and oxygen, ready availability, low cost, lower toxicity and metal-free reaction conditions. Among organocatalysts, L-proline is a readily obtainable naturally occurring amino acid and is easy to obtain in high enantiomeric purity. It has been reported as an eco-friendly catalyst for the synthesis of several heterocycles. Multi-component reactions (MCRs) have considerable ecological interest for use in the synthesis of biologically important compounds. The design of novel MCRs for the synthesis of diverse heterocycles has become as an important topic for medicinal and organic chemists. Heterocyclic compounds, especially nitrogenand oxygen-containing heterocyclic molecules in five and six-membered rings, play key roles in medicinal chemistry. Among them, oxazines and their derivatives are significant due a diversity of biological functions. Both natural and synthetic oxazines exhibit a wide range of biological activities, including anticoagulant activity, fungicidal activities, a-amino-3-hydroxy5-methyl-4-isoxazolepropionic acid receptor modulation activities, as well as analgesic and antispasmodic activities. In continuation of our research on MCRs and our ongoing program for the synthesis of complex organic compounds based on green chemistry protocols, we now report an efficient and green synthesis of 1,3-oxazine-4-thiones in the presence of