Der Mechanismus der Umlagerung substituierter Aminoacrylderivate

Thioacetic acid and dithioacetic acid react with alkynederivatives of the type (CH₃)₂N? C?C? CO? R ( 1 ) in the same way as other carboxylic acids: The addition to dimethylaminopropinal ( 1a ) at low temperatures yields, after rearrangement of the very instable primary adducts, Z-3-acetoxy-N,N-dimethyl-thioacrylamide ( Z-16 ) and Z-3-thioacetoxy-N,N-dimethylthioacrylamide ( Z-17 ) respectively. The structure of the two compounds can be proved by spectroscopic evidence of 16 and 18 , the latter being formed by elimination of thioketene from 17 . According to the distribution of S-atoms in 16 and 17 , two reaction pathways including 4-membered rings can be ruled out. Thus the rearrangement of 3-acyloxy-N,N-dimethyl-acrylamides most probably proceeds by a mechanism including a dipolar six-membered intermediate. This mechanism cannot be valid for the rearrangement of the adducts 2 of hydrohalogen acids, alcohols and amines to the alkyne-derivatives 1 . The acid-catalysed reaction of 3-chloro-3-dimethylamino-propenal ( 2 , X?Cl), labelled at position 1 with ¹³C, yields 3-chloro-N,N-dimethyl-acrylamide ( 3 , X?Cl), containing the label exclusively at position 3 . This result supports a mechanism including an immonium-oxetene 21 (X?Cl) as intermediate. - The experiments are in accord with kinetic investigations.     

Nafion-TMS- and TMS-Trifluoroacetate-Induced Rearrangements of Cyclopropyl Ketones - A procedure for the regioselective conversion of semibullvalenes to barrelenes

Trimethylsilyl trifluoroacetate (TMSTFA) and the polymer-supported sulfonate Nafion-TMS exhibit selective reaction modes in the opening of cyclopropyl ketones. The yields are generally high. Nafion-TMS rearranges the tricyclooctanones 1a and 1b to the bicyclooctenones 4a and 4b (while TMSTFA gives ring-opened adducts 6a,b ) with high regioselectivity. Aro-semibullvalenes ( 8a, 14, 17a,b ) are efficiently rearranged to arobarrelenes ( 7a, 13, 20a,b ) by both reagents. The latter rearrangements have also been achieved in mixtures of trifluoroacetic acid and tetramethylsilane (TMS), where the acid combines with an unidentified impurity of commercial TMS to form a strong electrophilic agent. The electrophile-assisted rearrangement of the naphtho-semibullvalenes 14a+b resulted in conversion to the naphthobarrelenes 13a+b with the opposite regioselectivity to that observed for the thermal equilibration at 220°.     

Synthesis of benzazepines and their rearrangement to quinolines and pyrrolo(2,3-b) quinolines

BECKMANN or SCHMIDT rearrangement of ethyl trans-4-oxo-1-phenyl-2-tetralincarboxylate ( 2 ) affords ethyl trans-2,3,4,5-tetrahydro-2-oxo-5-phenyl-1H-benzo [b] azepine-4-carboxylate ( 4 ). Mild treatment of trans-2,3,4,5-tetrahydro-1-methyl-2-oxo-5-phenyl-1 H-benzo-[b] azepine-4-carboxylic acid ( 7 ) with thionyl chloride and pyridine in dimethylformamide and subsequent reaction with an amine yields the corresponding benzazepine-4-carboxamide. If he it is applied during the preparation of the acid chloride, rearrangement occurs yielding cis and trans derivatives of hydrocarbostyril. 2,3,4,5-Tetrahydro-1,4-methano-1-methyl-5-phenyl-1 H-benzo-[b] azepinium chloride ( 25 ) reacts with primary or secondary amines to cis-tetrahydroquinoline derivatives. When heated above its melting point, trans-4,5-dihydro-2-methylamino-5-phenyl-3H-benzo-[b] azepine-4-carboxylic acid ( 29 ) rearranges with elimination of water to a mixture of cis-and trans-2,3,3a,4-tetrahydro-1-methyl-2-oxo-4-phenyl-1H-pyrrolo [2,3-b] quinoline ( 32 and 31 ). The reduction of 31 was investigated. The mechanisms of the rearrangements are discussed.     

Studies on sulfinatodehalogenation. XX. Sodium dithionite-initiated addition of per- and polyfluoroalkyl iodides to cyclic enol ethers and chemical conversions of the products

Per- and polyfluoroalkyl iodides [R_FI, R_F=Cl(CF₂)₄, 1a ; Cl(CF₂)₆, 1b ; Cl(CF₂)₈, 1c ; n-C₆F₁₃, 1d ; n-C₈F₁₇, 1e ] reacted with cyclic enol ethers such as 2,3-dihydrofuran (2) and 3,4-dihydro-2H-pyran (3) in aqueous acetonitrile in the presence of sodium dithionite and sodium bicarbonate at room temperature (10–15°C) to give the corresponding 2-(F-alkyl) hemiacetals in high yields. The adducts were oxidized with Ce(NH₄)₂(NO₃)₆ in acetonitrile or reduced with LiAlH₄ in ether to form the corresponding 2-(F-alkyl)lactones or diols respectively in good yields. In the presence of p-toluenesulfonic acid, the adducts were refluxed in benzene and CH₃CN to produce the corresponding 2,3-dihydro-4-(F-alkyl) furan and 3,4-dihydro-5-(F-alkyl)-2H-pyran. This is a new and effective method for preparing these useful organofluorine compounds.     

Carbamoylation of B6 vitamins

The reaction of B₆ vitamins 1–3 with cyanate, in the presence of equivalent amounts of hydrochloric acid, yields different adducts according to the structure of the starting material. Regiospecific attack on the amino group or the phenolic hydroxy group was found for 2a,b and 3a,b , respectively. From the aldehydes 1a,b , the 2H-pyrido[3,4-e]-1,3-oxazin-2-ones 7a,b were obtained through an attack on both the phenolic and aldehyde group.     

Photoisomerization pathways of 8,16-methno[2.2]metacyclopane-1,9-diene. A model case for adiabatic electrocyclic ring closure in the excited singlet state

The title compound 1b ideally meets the theoretical requirements for the occurrence of an adiabatic photoisomerization in the lowest excited state (¹ 1b *) and, indeed, the predominant primary photoreaction observed is the conversion to its fluorescent valence isomer 10b, 10c-methano-cis-10b 10c-dihydropyrene (¹ 1a *). The mechanism for the formation often previously observed photoproduct 8b, 9a-dihydro-9H - cyclopropa[e]pyrene ( 4a ) has been analyzed in some detail (Scheme). Below ? 30°C the reaction path consists of a three quantum process (two di-π-methane rearrangements and photochemical 1,7-H shift) involving two thermally stable, but light-sensitive isomers 8,11b-methanocyclodeca[cde]naphthalene ( 2b ) and 9H -cyclohepta[def]-phenanthrene ( 3b ). At room temperature the rearrangement 2b→4a proceeds with a single excitation step bypassing the ground state intermediate 3b . Finally, upon prolonged irradiation of ( 4a ), the methylene group is lost to yield pyrene. Compound 2b completes the series of all possible adducts of methylene to a C?C bond of pyrene.     

Reaktionen der valenzpolaromeren Ketenform mesoionischer Heterocyclen mit 3-Dimethylamino-2H-azirinen

Reactions of valencepolaromeric ketenes of mesoionic heterocyles with 3-dimethylamino-2H-azirines Reactions of the 3-dimethylamino-2H-azirines 1a and 1b with the mesoionic oxazole 5 and the mesoionic dithiole 6 in acetonitrile at room temperature yield the 1:1 adducts 11 , 12 , 19 and 20 , respectively (Schemes 5 and 8). These products can be formulated as adducts of the aminoazirines and the ketenes 5a and 6a , which are valence polaromeric forms of the mesoionic heterocycles 5 and 6 (Scheme 2). The structure of the adducts has been elucidated by spectral data and their comparison with the data of (Z)- 11 , the structure of which has been established by X-ray [19]. Oxidation of the 1:1 adducts with KMnO₄ in a two-phase system yields 4-dimethylamino-3-oxazolin-2-ones (cf. Scheme 6) by clevage of the exocyclic C,C-double bond. A mechanism for the formation of the adducts is given in Scheme 9: Nucleophilic attack of 1 on the ketene leads to a primary adduct of type a , which undergoes clevage of the former N(1), C(2)-azirine bond to give adducts of type 11 or 19 . The N(1), C(2)-ring opening of 1a in the reaction with ketenes contrasts with the N(1), C(3)-opening of 1a in the addition with, for instance, isothiocyanates. These different ring openings are explained by the difference in nucleophilicity of the heteroatoms X and Y in a ′ (Scheme 10).     

3-Oxo-1,2-benzoisothiazoline-2-acetic acid 1,1-dioxide derivatives. I. Reaction of esters with alkoxides

Reaction of 3-oxo-1,2-benzoisothiazoline-2-acetic acid alkyl esters 1,1-dioxide ( 1a-d ) with alkaline alkoxides was carried out under various conditions. Under mild conditions, o-(N-carboxymethylsulfamyl)benzoic acids dialkyl esters ( 2a-d ) were obtained with good yields. Reaction of 1a-d or 2a-d with sodium alkoxides under drastic conditions afforded 4-hydroxy-2H-1,2-benzothiazine-3-carboxylic acid alkyl esters 1,1-dioxide ( 3a-d ). Transesterification was observed when esters 1b-d were treated with sodium methoxide in methanol. Esters 3a-d were hydrolyzed in concentrated aqueous sodium hydroxide affording the acid 6 . Attempts to recrystallize 6 from water resulted in its decarboxylation to give 2H-1,2-benzothiazine-4-(3H)one 1,1-dioxide (7). Compound 6 could not be obtained by acid hydrolysis of esters 3a-d or by rearrangement of 3-oxo-1,2-benzoisothiazoline-2-acetic acid 1,1-dioxide ( 8 ). Different experimental evidence supports the suggestion that rearrangement took place by ethanolysis of the carboxamide linkage affording the open sulfonamides (fast step) followed by a Dieckmann cyclization (slow step). It was demonstrated that transesterification took place in the open sulfonamides 2 .     

Synthesis of (R)-1,2,11-trihydroxy-, (R)-2,11-, and (R)-2,10-dihydroxyaporphines — non naturally occurring aporphine alkaloids from pukateine and thebaine

The synthesis of (R)-2,10-dihydroxyaporphine ( 3a ), (R)-2,10-dihydroxy-N-n-propylnoraporphine ( 3b ) from thebaine and (R)-2,11-dihydroxyaporphine (7), and 1,2,11-trihydroxyaporphine ( 9 ), from pukateine is reported. The rearrangement of thebaine and northebaine with methanesulfonic acid to 1a and 1b with subsequent N-propylation gave 1b . Tetrazolyation of 1a, 1b and hydrogenolysis of 2a and 2b on Pd/C in acetic acid with subsequent O-demethylation with hydrobromic acid (48%) led to 3a and 3b . R(-)-2,11-Dihydroxyaporphine ( 7 ) was prepared by lithium/ammonia reduction of pukateine. (R)-1,2,11-Trihydroxyaporphine ( 9 ) was synthesized by reaction of pukateine with boron tribromide in dichloromethane.     

Säure-Additionen an ‘Push-Pull’-Enine. Erste Beobachtung einer Umlagerung von 5-Chloro-5-(dialkylamino)pentadienalen

Reaction of ‘Push-Pull’ Enynes with Acids. First Observation of a Rearrangement of 5-Chloro-5-(dialkylamino)pentadienals ‘Push-pull’-enynes 7 react easily with HCl as well as with AcOH to give 5-amino-5-chloropentadienals 8 and 5-(acetoxy)-5-aminopentadienals 13 as well as the corresponding ketones. In view of a postulated rearrangement of compounds 8 and 13 (Scheme 2), both types of compounds have been treated with traces of acid. While no definite reaction is observed in case of 13 , HCl-addition products 8 easily and quantitatively rearrange to give 2H-pyran-2-iminium chlorides 10 which are the postulated intermediates of the rearrangement 8 → 12 (Scheme 2).     

Acetylene mit Elektronendonator und Elektronenakzeptorgruppen

Acetylenes having both electrondonating and electronaccepting groups ( 1 ) may be obtained in good yield from the correspondingly substituted olefines via bromination and elimination of HBr. The reaction of the acetylene aldehyde 1a with proton acids yields, after rearrangement of the primary adducts, the β-substituted acrylamides. Addition of nucleophiles leads to the β-disubstituted α.β-unsaturated carbonyl compounds. With hydrazines one obtains pyrazoles and pyrazolones. The acetylenes 1 undergo [2+2]-, [2+3]- and [2+4]-cycloaddition reactions.     

Photolyse von 3-Methyl-2, 1-benzisoxazol (3-Methylanthranil) und 2-Azido-acetophenon in Gegenwart von Schwefelsäure und Benzolderivaten

Photolysis of 3-Methyl-2, 1-benzisoxazole (3-Methylanthranil) and 2-Azido-acetophenone in the Presence of Sulfuric Acid and Benzene Derivatives Irradiation of 3-methylanthranil ( 1 ) in acetonitrile in the presence of sulfuric acid and benzene, toluene, p-xylene, mesitylene or anisole with a mercury high-pressure lamp through a pyrex filter yields beside varying amounts of 2-amino-acetophenone ( 3 ) and 2-amino-5-hydroxy- ( 4a ) and 2-amino-3-hydroxy-acetophenone ( 4b ) the corresponding diphenylamine derivatives 5 (see Table 1). In the case of toluene and anisole mixtures of the corresponding ortho- and para-substituted isomers ( 5b, 5d or 5g, 5i respectively), but no meta-substituted isomers ( 5c or 5h ) are obtained. In addition to these products, the irradiation of 1 in the presence of anisole yields also 2-amino-5-(4′-methoxyphenyl)-acetophenone ( 7 ), 2-amino-3-(4′-methoxyphenyl)-acetophenone ( 8 ) and 2-methoxy-9-methyl-acridine ( 6 ; see Scheme 1). The latter product is also formed thermally by acid catalysis from the diphenylamine derivative 5i . Irradiation of 2-azido-acetophenone ( 2 ) in acetonitrile solution in the presence of sulfuric acid and benzene leads to the formation of 1, 3, 4a, 4b, 5a and 9 (see Table 2). Compounds 3, 4a, 4b and 5a are also obtained after acid catalyzed decomposition of 2 in the presence of benzene. Thus, it is concluded that irradiation of 1 or 2 in the presence of sulfuric acid yields 2-acetyl-phenylnitrenium ions 10 in the singlet ground state which will undergo electrophilic substitution of the aromatic compounds, perhaps via the π-complex 11 (see Scheme 2).     

[4+2]-Cycloadditionen von 1,2-Dicyanocyclobuten und seine thermische Ringöffnung zum 2,3-Dicyanobutadien-1,3

Facile synthetic routes to 1,2-dicyanocyclobutene ( 3 ), cyclobutene-1,2-dicarboxylic acid ( 56 ) and derivatives thereof are presented, starting from 1,2-dicyanocyclobutane ( 1 ), a commercially available acrylonitrile cyclodimer. The favored mode of [4+2]-cycloadditions of 3 to cyclic dienes with sp³carbon atoms is the endo-addition (above 90% relative yields of adducts with endo-cyclobutane ring). Exo-cycloaddition, however, is preferred by dienes having no sp³-carbon atom (e.g. furane). Cyclisation reactions involving cis-vicinal substituents in [4+ 2]-cycloadducts afford (m.n. 2)-azapropellanes 18 , 74 and 77 . ¹H- and ¹³C-NMR. spectra of the stereoisomeric adducts are discussed in detail. The structures of the furane adducts 14 and 15 were determined by ¹H-NMR. using the shift reagent Eu(dpm)₃. Reactive butadienes 32 , 53 - 55 are obtained in high yield and purity by gasphase thermolysis (380–420°) of the correspondingly substituted cyclobutenes. 2,3-Dicyanobutadiene-l, 3 ( 32 ) gives good yields of [4 + 2]-cycloadducts with strained cycloolefines, moderate yields with vinylethers and non-activated olefins, and no adducts at all with electrophilic dienophiles (8.g. maleic anhydride, fumaronitrile). Thus, reactions of 32 are typical Diels-Alder reactions with ‘inverse electron demand’. Some of these primary [4+2]-cycloadducts ( 38 , 39 and 45 ) were dehydrogenated to new aromatic ortho-dinitriles 46 - 48 .     

Preparation of 1,2,5-thiadiazole-3-carboxaldehydes

1,2,5-Thiadiazole-3-carboxaldehydes 1a-c were prepared by the acid-catalyzed decomposition of 3-azido-methyl-1,2,5-thiadiazoles 2a-c in 68-83% yields, respectively. Pyrolysis of 2a and 2b afforded the imidazoles 4a and 4b in low yields. NBS -bromination of 1a and 1b gave the corresponding carboxylic acids 10a and 10b via acid bromides 9. Azides 2a and 2b gave the s-triazines 8a and 8b on treatment with NBS.     

Octacarbonyldicoblat-Inauced (1,3) H Shits in 1-Methylallenecarboxylates and Allenic Lactones

The allenecarboxylates 1a , b and allenic lactones 4a , b undergo thermally induced (1,3) H Shifts in the presence of Co₂(CO)₈. The non-isolated 1,3-dienes 2a , b react further affording the Diels-Alder Adducts 3a , b Scheme 1 in high yields. These adducts were not formed in the case of the 2-vinybutenolides 5a , b . On irradiationin the presence of Co₂(CO)₈ or Mn₂(Co)₁₀, the studied allenes reacted in a different manner, yielding either cyclization products 7 and 8 (Scheme 3) or products 9 and 10 , formed via H abstracton and solvent addition (Schemes 4 and 5).     

Synthese und Reaktionen 8-gliedriger Heterocyclen aus 3-Dimethylamino-2,2-dimethyl-2H-azirin und Saccharin bzw. Phthalimid

Synthesis and Reactions of 8-membered Heterocycles from 3-Dimethylamino-2,2-dimethyl-2H-azirine and Saccharin or Phthalimide 3-Dimethylamino-2,2-dimethyl-2H-azirine ( 1 ) reacts at 0-20° with the NH-acidic compounds saccharin ( 2 ) and phthalimide ( 8 ) to give the 8-membered heterocycles 3-dimethylamino-4,4-dimethyl-5,6-dihydro-4 H-1,2,5-benzothiadiazocin-6-one-1,1-dioxide ( 3a ) and 4-dimethylamino-3,3-dimethyl-1,2,3,6-tetrahydro-2,5-benzodiazocin-1,6-dione ( 9 ), respectively. The structure of 3a has been established by X-ray (chap. 2). A possible mechanism for the formation of 3a and 9 is given in Schemes 1 and 4. Reduction of 3a with sodium borohydride yields the 2-sulfamoylbenzamide derivative 4 (Scheme 2); in methanolic solution 3a undergoes a rearrangement to give the methyl 2-sulfamoyl-benzoate 5 . The mechanism for this reaction as suggested in Scheme 2 involves a ring contraction/ring opening sequence. Again a ring contraction is postulated to explain the formation of the 4H-imidazole derivative 7 during thermolysis of 3a at 180° (Scheme 3). The 2,5-benzodiazocine derivative 9 rearranges in alcoholic solvents to 2-(5′-dimethylamino-4′,4′-dimethyl-4′H-imidazol-2′-yl) benzoates ( 10 , 11 ), in water to the corresponding benzoic acid 12 , and in alcoholic solutions containing dimethylamine or pyrrolidine to the benzamides 13 and 14 , respectively (Scheme 5). The reaction with amines takes place only in very polar solvents like alcohols or formamide, but not in acetonitrile. Possible mechanisms of these rearrangements are given in Scheme 5. Sodium borohydride reduction of 9 in 2-propanol yields 2-(5′-dimethylamino-4′,4′-dimethyl-4′H-imidazol-2′-yl)benzyl alcohol ( 15 , Scheme 6) which is easily converted to the O-acetate 16 . Hydrolysis of 15 with 3N HCl at 50° leads to an imidazolinone derivative 17a or 17b , whereas hydrolysis with 1N NaOH yields a mixture of phthalide ( 18 ) and 2-hydroxymethyl-benzoic acid ( 19 , Scheme 6). The zwitterionic compound 20 (Scheme 7) results from the hydrolysis of the phthalimide-adduct 9 or the esters 11 and 12 . Interestingly, compound 9 is thermally converted to the amide 13 and N-(1′-carbamoyl-1′-methylethyl)phthalimide ( 21 , Scheme 7) whose structure has been established by an independent synthesis starting with phthalic anhydride and 2-amino-isobutyric acid. However, the reaction mechanism is not clear at this stage.     

1-Amino-2-phthalimido-diazen-1-oxide: Bildung,Eigenschaften und Fragmentierungen in Imido- und Amino-nitrene

1-Amino-2-phthalimido-diazene-1-oxides: Formation, Properties and Fragmentation Reactions into Imido- and Amino-nitrenes¹) Oxidatively generated phthalimido-nitrene ( 1 ) reacts with the nitrosoamines 2a-d (see Scheme 1) to give the corresponding (Z)-1-amino-2-phthalimido-diazene-1-oxides 3a-d in good yields. With the O-nitroso compound 2e , no addition of the nitrene 1 took place. The constitution the adducts 3 (R = NR′₂) is deduced from their spectroscopic properties (UV., IR., ¹H-NMR. and MS.) as compared to those of (Z)-1-aryl- and (Z)-1-alkyl-2-phthalimido-diazene-1-oxides 3 (R = aryl and alkyl, resp.). The (Z)-configuration of 3 (R = NR′₂) follows from an X-ray analysis which is reported separately. Compounds 3 (R = NR′₂) are cleaved photolytically as well as by acid to the corresponding nitrosoamines 2 (R = NR′₂) and the nitrene 1 , which could be trapped by cyclohexene to give 40% of 7-phthalimido-7-azabicyclo [4.1.0]heptane ( 8 ) and by dimethylsulfoxide to yield 96% of S, S-dimethyl-N-phthalimido-sulfoximide ( 13 ). Nucleophilic attack leads to fragmentation of 3 (R = NR′₂) into derivatives of phthalic acid and degradation products of intermediate aminonitrenes 24 corresponding to the respective nitrosoamines 2 (R = NR′₂) with loss of oxygen. A general rationalization for the formation of 24 includes as a key step of N- to C-migration of the O-atom (see Scheme 6). The final fate of 24 is depending on the type of the nucleophile used. Thus, hydrazinolysis of 3b and of 3c generates besides N, N′-phthaloylhydrazine ( 15 ), morpholine ( 14 ) from 3b and 1, 3-dihydroisoindole ( 16 ) together with 6′-methylidene-1, 2, 3, 4-tetrahydronaphthalene-2-spiro-1′-cyclohexa-2′, 4′-diene ( 17 ) from 3c (see Scheme 5). Treatment of 3b and of 3c with sodium methylate leads in both reactions to monomethyl phthalate ( 33 ) and, with 3b , to 1, 2-dimorpholinodiazene ( 31 ) and, with 3c , to 17 (see Scheme 7). Finally, the reaction of 3b with diethylamine generates N, N-diethylphthalamic acid ( 36 ), morpholine ( 14 ), 1,1,4,4-tetraethyl-2-tetrazene( 34 ) and l,l-diethyl-4,4-(3-oxapentamethylene)-2-tetrazene ( 35 ) (see Scheme 8).     

Favorskii Rearrangement in the Reaction of 3-(1-Adamantyl)-1-chloro-2-propanone with Amines

The reaction of 3-(1-adamantyl)-1-chloro-2-propanone with amines [diethylamine, (1-adamantyl)methylamine, p-toluidine, and piperidine] in diethyl ether at room temperature involves the Favorskii rearrangement and yields N,N-disubstituted amides of 3-(1-adamantyl)propanoic acid.     

1,2,4-benzothiadiazine 1,1-dioxides 3. Reactions of 2-aminobenzenesulfonamide with chloroalkyl isocyanates

Reactions of 2-aminobenzenesulfonamide ( 1 ) with allyl, methyl, 2-chloroethyl aor 3-chloropropyl isocyanates gave 2-(methylureido)-, 2-(allylureido)-, 2-(2′-chloroethylureido)- and 2-(3′-chloropropylureido)-benzene sulfonamides 3a,b and 7a,b in excellent yields. Treatment of 3a,b at refluxing temperature of DMF afforded 2H-1,2,4-benzothiadiazin-3(4H)-one 1,1-dioxide ( 4 ) in good yield. However, when compounds 7a,b were refluxed in 2-propanol, 3-(2′-aminoethoxy)-2H-1,2,4-benzothiadiazine 1,1-dioxide ( 11a ) and 3-(3′-aminopropoxy)-2H-1,2,4-benzothiadiazine 1,1-dioxide ( 11b ) were obtained in a form of the hydrochloride salts 10a,b in 87% and 78% yields respectively. Heating 11b in ethanol gave a dimeric form of 2H-1,2,4-benzothiadiazin-3(4H)-one 1,1-dioxide and 3-(3′-aminopropoxy)-2H-1,2,4-benzothiadiazine 1,1-dioxide ( 12 ) in 55% yield. Treating of 7a,b or 11a,b with triethylamine at the refluxing temperature of 2-propanol afforded 3-(2′-hydroxyethylamino)-2H-1,2,4-benzothiadiazine 1,1-dioxide ( 2a ) and 3-(3′-hydroxypropylamine)-2H-1,2,4-benzothiadiazine 1,1-dioxide ( 2b ) via a Smiles rearrangement.