2-Amino-4H-3,1-benzothiazines from Arylcyclopropanes: Crystal Structure of the Product of N1-(2-Cyclopropylphenyl)-N2-(2-ethylphenyl)thiourea Rearrangement

Федотов, А. Н.; Трофимова, Е. В.; Sidorov, V. A.; Potekhin, K. A.; Romanov, V. A.; Mochalov, S. S.; Зефиров, Н. С.

doi:10.1007/s10631-005-0076-4

Cited by 5 publications

(3 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Since the signal of the NH group in the 1 H NMR spectrum of the solution of the compound obtained from thiourea 3b appears at 7.25-7.33 ppm (see Table 2 and our previous work [24]), which is in accord with the chemical shifts of the corresponding protons of the compounds 4a-i, and 5a,c,d (Table 2) and with the chemical shifts of the corresponding protons described in the literature for this type of heterocyclic compounds [20][21][22][23], it is quite likely that the heterocyclic product, which is formed upon the rearrangement of 3b, is present in solution as 2-amino-4H-3,1-benzothiazine 5b, though that this product exists in the crystal as tautomer 6b.…”

mentioning

confidence: 84%

“…It was only in 2005 that we were the first to publish the results of our X-ray diffraction study of the structure of the heterocyclic compound formed by the action of sulfuric acid on N (1) -(2-cyclopropylphenyl)-N (2) -(2-ethylphenyl)thiourea 3b [24]. The 1 H NMR spectrum of the heterocyclic compound formed in this reaction taken in DMSO-d 6 was used to identify it as 4-ethyl-2-(2'-ethylphenyl)amino-4H-3,1-benzothiazine (5b), while the results of an X-ray diffraction structural study of the crystal structure corresponded to 4-ethyl-2-(2'-ethylphenyl)imino-4H-3,1-benzothiazine (6b).…”

mentioning

confidence: 99%

See 1 more Smart Citation

Synthesis of 2-amino-4H-3,1-benzoxazines and 2-amino-4H-3,1-benzothiazines by the rearrangement of o-cyclopropylphenylureas and o-cyclopropylphenylthioureas

Федотов

Трофимова

Romanov

et al. 2008

Chem Heterocycl Comp

Self Cite

View full text Add to dashboard Cite

Syntheses are reported for 2-cyclopropylphenylureas and 2-cyclopropylphenylthioureas and the behavior of these compounds was studied under conditions for the acid-catalyzed opening of the cyclopropyl ring. Upon the action of concentrated sulfuric acid or trifluoroacetic acid, these ureas and thioureas can undergo rearrangement to the corresponding 3,1-benzoxazines and 3,1-benzothiazines.Functionally-substituted cyclopropanes, which have now become readily available, are finding increasing use as starting compounds in the synthesis of various organic compounds produced by the transformation of the three-membered ring upon the action of specific reagents. These transformations may yield either saturated or unsaturated acyclic products of opening of the cyclopropyl ring [1-4] or carbo-and heterocycles [5][6][7][8][9][10][11]. An especially large number of studies have been devoted to donor-acceptor functionally-substituted cyclopropanes [11]. The reactions in this case proceed predominantly with the participation or effect of the substituents directly bound to the three-carbon ring. There has been considerably less work on the transformations of cyclopropane compounds, in which the substituents, not directly bound to the cyclopropane ring, participate in the reaction. Nevertheless, examples of such transformations [9,[12][13][14] show that the synthetic scope of functionally-substituted cyclopropanes may be considerably expanded. Here, definite promise is found in intramolecular acid-catalyzed ortho-substituted arylcyclopropanes due to the unique ortho-orienting effect of the cyclopropane substituent in electrophilic nitration reactions [15][16][17]. These reagents are now readily available.In a search for new examples of the intramolecular rearrangement of ortho-functionally-substituted arylcyclopropanes, we synthesized 2-cyclopropylphenylureas and 2-cyclopropylphenylthioureas and studied their transformations in trifluoroacetic and concentrated sulfuric acids. We assumed that the acid-catalyzed opening of the cyclopropane ring in suitable cyclopropylureas and cyclopropylthioureas would initiate reaction of the resultant benzylic carbenium ion with the internal nucleophile (urea or thiourea fragment) to form 2-amino-3,1-benzoxazines and 3,1-benzothiazines or isomeric compounds. _______ * Deceased. __________________________________________________________________________________________

show abstract

mentioning

confidence: 84%

mentioning

confidence: 99%

Synthesis of 2-amino-4H-3,1-benzoxazines and 2-amino-4H-3,1-benzothiazines by the rearrangement of o-cyclopropylphenylureas and o-cyclopropylphenylthioureas

Федотов

Трофимова

Romanov

et al. 2008

Chem Heterocycl Comp

Self Cite

View full text Add to dashboard Cite

show abstract

“…To confirm the structure of the product, 1 H NMR spectra recorded in different deuterated solvents were studied. The compound produces a signal at  6.7 in CDCl 3 , which is in accord with the chemical shift of the exocyclic N-H group [20,21] readily undergoes tautomeric transformation from 4a into 3a. It can be confirmed that solvent conditions play an important role in affecting the tautomeric equilibrium.…”

Section: Resultsmentioning

confidence: 54%

Tandem addition-cyclization reaction catalyzed by ytterbium chloride: An efficient one-step synthesis of 2-amino-4H-3,1-benzothiazine

Huang

et al. 2013

Chin. Sci. Bull.

View full text Add to dashboard Cite

show abstract

Chemoselective reactions under solvent-free conditions: lanthanide-catalyzed syntheses of 2-amino-3,1-benzothiazines and 3,4-dihydroquinazoline-2-thiones

Yao

et al. 2014

RSC Adv.

View full text Add to dashboard Cite

2-Amino-4H-3,1-benzothiazines from Arylcyclopropanes: Crystal Structure of the Product of N1-(2-Cyclopropylphenyl)-N2-(2-ethylphenyl)thiourea Rearrangement

Cited by 5 publications

References 10 publications

Synthesis of 2-amino-4H-3,1-benzoxazines and 2-amino-4H-3,1-benzothiazines by the rearrangement of o-cyclopropylphenylureas and o-cyclopropylphenylthioureas

Synthesis of 2-amino-4H-3,1-benzoxazines and 2-amino-4H-3,1-benzothiazines by the rearrangement of o-cyclopropylphenylureas and o-cyclopropylphenylthioureas

Tandem addition-cyclization reaction catalyzed by ytterbium chloride: An efficient one-step synthesis of 2-amino-4H-3,1-benzothiazine

Chemoselective reactions under solvent-free conditions: lanthanide-catalyzed syntheses of 2-amino-3,1-benzothiazines and 3,4-dihydroquinazoline-2-thiones

Contact Info

Product

Resources

About