5-((8-Hydroxyquinolin-5-yl)diazenyl)-3-methyl-1H-pyrazole-4-carboxylic Acid

Round 1

Reviewer 1 Report

The authors report information about new compound - 5 - ((8-Hydroxyquinolin-5-yl) diazenyl) -3-methyl-1H-pyrazole-4-carboxylic acid. It looks like that studies have been properly planned and performed carefully. The only comments I have regarding the following:
1. The Scheme 1. - the authors wrote “ArH = 8-hydroxyquinoline”, such notation is confusing. At first, I was wondering what this aromatic derivative was used for the synthesis. In literature, a commonly used abbreviation for 8-hydroxyquinoline is 8-HQ (8HQ).
2. Some sentences start with but or because. The article is formal writing form and in my opinion these word should not start a sentence.

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Authors described the synthesis and complete characterization of novel 5-((8-hydroxyquinolin-5-yl)diazenyl)-3-methyl-1H-pyrazole-4-carboxylic acid. I consider that manuscript meets all requirements to be published in “Molbank” after major revision. The English might be carefully revised. In particular, the IR, ¹H NMR, ¹³C NMR, ¹⁵N NMR, 2D NMR, UV-Vis, and HRMS spectra for compounds 3 and 4 must be included in the Supplementary Material. Moreover, COSY and NOESY experiments for compounds 3 and 4 must be included to support that the azo-coupling was done in C-5 of 8-hydroxyquinoline. Additional comments and suggestions are included:    

(1) See abstract, line 17. fully characterized by instead of characterized by:

(2) See abstract, line 17. 2D NMR spectroscopy and HRMS spectrometry instead of 2D NMR, HRMS spectroscopic methods. The MS technique does not work using the spectroscopy.

(3) See line 43. obtain the desired product instead of obtain desired product.

(4) See Scheme 1. (a) for the formation of 3 from 2, the solvent, base and reaction time might be indicated on the arrow, and (b) for the formation of 4 from 3, the temperature, base and reaction time might be indicated on the arrow.

(5) See Scheme 1. It is very confuse because the structure 3 is repeated twice. It might be improved.

(6) See line 63. regioselectively in C-5 position instead of exclusively in C-5 position.

(7) Authors mention that “the experimental NMR data shows that coupling took place exclusively in C-5 position”. Thus, both COSY and NOESY experiments might be included in the Supplementary Material to support it (it is mandatory).

(8) See lines 60-69. From a structural analysis point of view, I did not find an explanation of IR, UV-Vis, 1D and 2D NMR. It is exceedingly incomplete. The most important vibration modes, transitions bands, proton and carbons signals, respectively, might be explained.    

(9) See line 74. Authors recorded “¹⁵N-NMR spectra”. However, I did not find an explanation of this result in the manuscript. Moreover, it might be included in the Supplementary Material.

(10) See Synthesis of ethyl 5-((8-hydroxyquinolin-5-yl)diazenyl)-3-methyl-1H-pyrazole-4-carboxylate (3). (a) The stoichiometric amounts (mg and mmol) for all chemical reagents might be included, (b) all coupling constants (J) might be reported with only one decimal after the point, (c) for ¹H NMR reporting data is absent two protons; thus, it might specified (i.e. OH and NH is absent), (d) the compound 3 has 16 carbon signals while you are reporting 15 carbon signals ¿which one is overlapped?, (e) if compound 3 has 5 different nitrogen nucleus ¿why did you report only one nitrogen signal in ¹⁵H NMR reporting data?, and finally (f) the type of UV-Vis absorption at 393 nm might be indicated.    

(11) See Synthesis of ethyl 5-((8-hydroxyquinolin-5-yl)diazenyl)-3-methyl-1H-pyrazole-4-carboxylate (3). The assignation of most vibration modes for IR data might be indicated in parenthesis (i.e. n N-H, n O-H, among others).

(12) See synthesis of 5-((8-hydroxyquinolin-5-yl)diazenyl)-3-methyl-1H-pyrazole-4-carboxylic acid (4). The assignation of most vibration modes for IR data might be indicated in parenthesis (i.e. n N-H, n O-H, among others).

(13) See synthesis of 5-((8-hydroxyquinolin-5-yl)diazenyl)-3-methyl-1H-pyrazole-4-carboxylic acid (4). (a) The stoichiometric amounts (mg and mmol) for all chemical reagents might be included, (b) all coupling constants (J) might be reported with only one decimal after the point, (c) all multiplets might be reported as a range like xx.x-xx.x (m, xxH), (d) for ¹H NMR reporting data is absent one proton; thus, it might specified (i.e. NH is absent), (e) ¿where is ¹⁵H NMR reporting data for compound 4?, and finally (f) the type of UV-Vis absorption at 385.5 nm might be indicated.

(14) The IR, ¹H NMR, ¹³C NMR, ¹⁵N NMR, 2D NMR, UV-Vis, and HRMS spectra for compounds 3 and 4 must be included in the Supplementary Material. Moreover, COSY and NOESY experiments for compounds 3 and 4 must be included to support that the azo-coupling was done in C-5 of 8-hydroxyquinoline.

(15) A short conclusion might be included. 

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Authors described the synthesis and complete characterization of novel 5-((8-hydroxyquinolin-5-yl)diazenyl)-3-methyl-1H-pyrazole-4-carboxylic acid. I consider that manuscript meets all requirements to be published in “Molbank” after minor revision. Additional comments and suggestions are included:    

(1) See abstract, line 17. full instead of fully.

(2) See supplementary material. Figure S3. DEPT-135 spectrum of the compound (3) instead of Figure S3. ¹³C DEPT135 spectrum of the compound (3).

(3) See supplementary material. Figure S11. DEPT-135 spectrum of the compound (4) instead of Figure S11.¹³C DEPT135 spectrum of the compound (4).

(4) See Figures S1 and S2. The residual signals of the deuterated solvent might be indicated with any symbol to avoid confusions for potential readers.

(5) See Figure S6. I consider that HMBC ¹H-¹⁵N spectrum of the compound (3) is a little difficult to interpret because you are using a nitrogen-containing deuterated solvent ¿Did you observe N1, N5b, NH2´ and N3’ signals? ¿How did you confirm that the signal corresponding to N1? ¿where are the rest N5b, NH2´ and N3’ signals?

(6) See figures S10 and S11. These NMR spectra could be taken with more scans to improve the resolution.  

(7) See lines 150-151. The assignation of the relevant vibrations modes might be indicated using the corresponding symbol such as xxxx (nN-H), xxxx (nO-H), xxxx (nN=N), xxxx (nC=N), xxxx (nN=N), xxxx (n_asC-O), xxxx (n_sC-O), xxxx (dC-N), among others.

(8) See lines 111-112. Authors mention that “UV-Vis spectra were recorded on a Jasco V-530 spectrometer and the samples were dissolved in 96% ethanol”. The concentration of both solutions (i.e. xx.xx μM) might be indicated.

(9) See lines 150-151. The assignation of the relevant vibrations modes should be indicated using the corresponding symbol such as xxxx (nN-H), xxxx (nO-H), xxxx (nN=N), xxxx (nC=N), xxxx (nN=N), xxxx (n_asC-O), xxxx (n_sC-O), xxxx (dC-N), among others.

(10) A short explanation about most relevant vibration modes might be included ¿how do you confirm the formation of 4 from 3 by IR spectrocopy?

(11) A short conclusion might be included (three or five lines).   

Author Response

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Author Response File: Author Response.pdf