Abstract: Certain benzothiazine compounds, metal complexes thereof and solutions of said compounds in essentially water-immiscible, liquid hydrocarbon solvents are disclosed. These compounds have in their 4-keto form, the structure: ##STR1## the corresponding enol of which has the structure: ##STR2## wherein x, n, R.sup.1, R.sup.2 and R.sup.3 are as defined in the specification and claims hereof. Particular metal values are recovered from their aqueous solutions by using the benzothiazine compounds dissolved in essentially water-immiscible, liquid hydrocarbon solvents. The extraction process involves contacting the metal value containing aqueous solution with the solution of the benzothiazine in essentially water-immiscible, liquid hydrocarbon solvent and stripping the metal from the loaded organic phase.

Abstract: 2-Methoxyethyl 4-hydroxy-2-methyl-2H-1,2-benzothiazine-3-carboxylate 1,1-dioxide is an advantageous ester precursor for piroxicam (4-hydroxy-2-methyl-N-2-pyridyl-2H-1,2-benzothiazine-3-carboxamide 1,1-dioxide), an antiinflammatory agent established in medical practice.

Abstract: Compounds of the formula ##STR1## wherein R.sub.1 is hydrogen, methyl or ethyl;R.sub.2 is methyl, ethyl or n-propyl; andY is hydrogen, methyl, methoxy, fluorine or chlorine;and non-toxic, pharmacologically acceptable salts thereof formed with an inorganic or organic base. The compounds as well as their salts are useful as antiphlogistics.

Abstract: 3,4-Dihydro-2H-1,2-benzothiazine 1,1-dioxides of the formula ##STR1## wherein Ph represents a substituted or unsubstituted 1,2-phenylene radical, R represents a substituted or unsubstituted benzopyrone radical, and R.sub.1 represents hydrogen or a substituted or unsubstituted hydrocarbon radical of aliphatic character, and their salts, possess antiinflammatory properties and are useful as medicaments.

Abstract: A novel process for preparing 4-hydroxy-2H-1,2-benzothiazine-3-carboxamide 1,1-dioxides is disclosed. The process involves the base catalyzed rearrangement of a saccharinacetamide of structure I to give II, ##STR1## wherein R.sup.1 is hydrogen or lower alkyl and R.sup.2 is lower alkyl, aryl or a heterocyclic ring selected from the group consisting of pyridyl, substituted-pyridyl, and thiazolyl. Compounds of the formula II have useful anti-inflammatory properties. In addition, they can be used as intermediates in the preparation of known anti-inflammatory agents.

Abstract: Process for production of 3,4-dihydro-2-methyl-4-oxo-2H-1,2-benzothiazine-3-carboxylic acid-1,1-dioxide by hydrolysis, in the presence of hydroxide ions, of an alkyl or aralkyl ester thereof followed by precipitation of the acid at pH below 6.0 and its use as an intermediate for the production of N-(2-pyridyl)-3,4-dihydro-2-methyl-4-oxo-2H-1,2-benzothiazine-3-carboxamid e-1,1-dioxide and the analogous N-(2-thiazolyl)-compound, effective antiinflammatory agents.

Abstract: A novel process for preparing 4-hydroxy-2H-1,2-benzothiazine-3-carboxamide 1,1-dioxides is disclosed. The process involves the base catalyzed rearrangement of a saccharinacetamide of structure I to give II, ##STR1## wherein R.sup.1 is hydrogen or lower alkyl and R.sup.2 is lower alkyl, aryl or a heterocyclic ring selected from the group consisting of pyridyl, substituted-pyridyl, and thiazolyl. Compounds of the formula II have useful anti-inflammatory properties. In addition, they can be used as intermediate in the preparation of known anti-inflammatory agents.

Abstract: A process for the synthesis of N-aryl-3,4-dihydro-2-alkyl-4-oxo-2H-1,2-benzothiazine-3-carboxamide 1,1-dioxides by treatment of N-aryl-N'-alkyl-N'-(2'-alkoxycarbonylbenzenesulfonyl)glycineamides, useful intermediates for said process, with an alkali or alkaline earth metal hydride in a reaction-inert solvent at 50.degree.-150.degree. C., said products being antiinflammatory agents.

Abstract: Compounds having the following structural formula are disclosed: ##STR1## wherein R.sub.1 is hydrogen or methyl and R.sub.2, and R.sub.3 are hydrogen or alkyl. These compounds are useful as anti-inflammatory agents, antipyretics, analgesics.