5-Vinyl-1H-tetrazole

Round 1

Reviewer 1 Report

Ostrovskii and coworkers reported the modified process for preparation of 5-vinyl-1H-tetrazole and studied their thermal stability and molecular structure and spectral properties. Without any doubt, the work addresses an important transformation and the method developed appears to be useful and may find some application in the future. This reviewer certainly appreciated the new methodology. Using previously known methods of synthesis it is impossible to obtain pure vinyltetrazole. Furthermore, impurities catalyze uncontrolled polymerization and occurs both in the crystalline phase (in bulk) and in solutions. The author solved this problem in the framework of this study and synthesized a stable NH-unsubstituted 5-vinyl-1H-tetrazole compound, which is not polymerize spontaneously. I recommend this manuscript for publication in Molbank Journal. However, before publication, the following points should be considered.

1.  The page 2, line 55-57 should be written “as In this context, recently we have disclosed the Palladium-catalyzed Mizoroki-Heck cross-coupling reactions reaction between N-methyl-5-vinyltetrazoles and aryl iodides in the presence of copper salts for the synthesis of 5-styryltetrazoles. [6, 7].”

2. Page 2, line 93, the number 1 should be bold

3. Page 2, scheme 2, typo mistake of “chatcoal” should be replace with “charcoal”

Author Response

The authors are grateful to the reviewer for a careful and scrupulous analysis of the manuscript.

1. The page 2, line 55-57 should be written “as In this context, recently we have disclosed the Palladium-catalyzed Mizoroki-Heck cross-coupling reactions reaction between N-methyl-5-vinyltetrazoles and aryl iodides in the presence of copper salts for the synthesis of 5-styryltetrazoles. [6, 7].”

Response: It has been corrected

2. Page 2, line 93, the number 1 should be bold

Response: It has been corrected and the text was corrected according to the comments of the second R.

3. Page 2, scheme 2, typo mistake of “chatcoal” should be replace with “charcoal”

Response: It has been corrected

Besides that “NH-unsubstituted” has been removed in the title and in text.

Author Response File: Author Response.docx

Reviewer 2 Report

The research work “NH-UNSUBSTITUTED 5-VINYL-1H-TETRAZOLE” by D. Krygina et al. concerns the synthesis and structural elucidation of high purified NH-substituted 5-vinyl-1H-tetrazole, resistant to spontaneous polymerization.

The manuscript requires minor revision.

Questions and comments related to the manuscript:

1) Please check the manuscript carefully and correct the typos:

L. 94: “chatcoal"

L. 238, 256, 260, etc.: "sm^-1"

L. 333 and 337: "40-50 °C." and "110oC." check the degrees Celsius sign

L. 342: "Yield 12.7 g. (67%)"

and others.

2) L. 83: "5-(β-dimethylaminoethyl)tetrazole 4 with a zwitter-ion structure was obtained" structure of zwitter-ion should be shown at scheme 2.

3) L. 90: the sentence "As it seen from Scheme 2 and as it followed from the synthesis method, we included an additional purification step of 5-β-dimethylaminoethyltetrazole with activated carbon, and also lowered the dissolution temperature of tetrazole 1 to 50 °C before crystallization from chloroform." is not clear, what temperature was used in the previous work?

4) In Table 7 check the name of the column "Product ions".

5) L. 340: "and approximately 1 g of finely-dispersed activated charcoal." omitted predicate.

6) L. 359: "1H NMR spectrum (500 MHz, DMSO-d6)", but in L. 419 NMR spectrometer "Bruker Avance III 400 MHz spectrometer" is provided.

7) L. 418: "1H-15N HMQC" there is no such speсtrum in the manuscript or supplementary.

Author Response

The authors are grateful to the reviewer for a careful and scrupulous analysis of the manuscript.

1) Please check the manuscript carefully and correct the typos:

1. 94: “chatcoal"
2. 238, 256, 260, etc.: "sm^-1"
3. 333 and 337: "40-50 °C." and "110oC." check the degrees Celsius sign
4. 342: "Yield 12.7 g. (67%)"

and others.

Response: It has been corrected

2) L. 83: "5-(β-dimethylaminoethyl)tetrazole 4 with a zwitter-ion structure was obtained" structure of zwitter-ion should be shown at scheme 2.

Response: It has been corrected

3) L. 90: the sentence "As it seen from Scheme 2 and as it followed from the synthesis method, we included an additional purification step of 5-β-dimethylaminoethyltetrazole with activated carbon, and also lowered the dissolution temperature of tetrazole 1 to 50 °C before crystallization from chloroform." is not clear, what temperature was used in the previous work?

Response: It has been clarified. Besides the phrase “At the first stage, as a result of 1,3-dipolar cycloaddition of dimethylammonium azide to β-dimethylaminopropionitrile in DMF 5-(β-dimethylaminoethyl)tetrazole with a zwitter-ion structure 4a was obtained, which precipitated [11]. At the second stage exhaustive alkylation in H₂O of the terminal dimethylamino group of 5-(β-dimethylaminoethyl)tetrazole in normal form 4b was carried out selectively, without affecting the tetrazole ring [10]” has been added.

4) In Table 7 check the name of the column "Product ions".

Response: It has been corrected to “cross-peaks”.

5) L. 340: "and approximately 1 g of finely-dispersed activated charcoal." omitted predicate.

Response: It has been added.

6) L. 359: "1H NMR spectrum (500 MHz, DMSO-d6)", but in L. 419 NMR spectrometer "Bruker Avance III 400 MHz spectrometer" is provided.

Response: We used two spectrometers. The solution ¹H, ¹³C{¹H} NMR spectra were recorded on a Bruker Avance III 400 MHz spectrometer in DMSO-d₆. The solution ¹H-¹⁵N HMBC NMR spectra was recorded on a Bruker Avance III 500 MHz. This information has been added to 3.3.5 subchapter.

7) L. 418: "1H-15N HMQC" there is no such speсtrum in the manuscript or supplementary.

Response: It has been corrected to HMBC.

Besides that, “NH-unsubstituted” has been removed in the title and in text.

Author Response File: Author Response.docx