Protolytic constants of nizatidine, ranitidine and N,N′-dimethyl-2-nitro-1,1-ethenediamine; spectrophotometric and theoretical investigation

Dumanović, D.; Juranić, Ivan O.; Dželetović, D.; Vasić, Vesna; Jovanović, Jovan

doi:10.1016/s0731-7085(96)01977-2

Cited by 30 publications

(28 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Light absorption above 300 nm is dramatically decreased in highly acidic media similar to NPM, which is in agreement with earlier work on RAN. 47,51 This was attributed to loss of conjugation due to protonation of the alkene carbon: 51 Thus, C-protonation in RAN should play a role under highly acidic conditions (pK a 2.19), 51 consistent with the predictions for NPM at B3. Note that the pK a of the tertiary nitrogen in the terminal dimethylamine group in RAN has been measured to be 8.1, 51 so it too will be protonated, but because it is far removed from the chromophore, it will not impact the spectrum.…”

Section: Acs Earth and Space Chemistrysupporting

confidence: 52%

“…The pK a values for tertiary amines are typically in the 8−10 range; 74 the pK a for the terminal tertiary amine in RAN has been reported to be 8.13. 51 Thus, under neutral to mildly acidic conditions, the tertiary nitrogen in NPM and the terminal tertiary amine in RAN should be protonated. There may also be a contribution in this region from the CC stretch.…”

Section: Acs Earth and Space Chemistrymentioning

confidence: 99%

See 1 more Smart Citation

Experimental and Theoretical Studies of the Environmental Sensitivity of the Absorption Spectra and Photochemistry of Nitenpyram and Analogs

Ezell

Wang

Shemesh

et al. 2019

ACS Earth Space Chem.

View full text Add to dashboard Cite

Neonicotinoid (NN) pesticides have widespread use, largely replacing other pesticides such as the carbamates. Hence, there is a need to understand their environmental fates at a molecular level in various media, especially water. We report here the studies of a nitroenamine NN, nitenpyram (NPM), in aqueous solution where the absorption cross sections in the actinic region above 290 nm are observed to dramatically decrease compared to those in nonaqueous solvents. Quantum chemical calculations show that addition of a proton to the tertiary amine nitrogen in NPM breaks the conjugation in the chromophore, shifting the absorption to shorter wavelengths, consistent with experiment. However, surprisingly, adding a proton to the secondary amine nitrogen leads to its immediate transfer to the NO 2 group, preserving the conjugation. This explains why the UV absorption of ranitidine (RAN), which has a similar chromophore but only secondary amine nitrogens, does not show a similar large blue shift in water. Photolysis quantum yields in aqueous NPM solutions were measured to be ϕ = 0.18 ± 0.07 at 254 nm, (9.4 ± 1.6) × 10 −2 with broadband radiation centered at 313 nm and (5.2 ± 1.1) × 10 −2 for broadband radiation centered at 350 nm (errors are 2σ). The major products in aqueous solutions are an imine that was also formed in the photolysis of the solid and a carboxylic acid derivative that is unique to the photolysis in water. Combining the larger quantum yields in water with the reduced absorption cross sections results in a calculated lifetime of NPM of only 5 min at a solar zenith angle of 35°, typical of 40°N latitude on April 1. The products do not absorb in the actinic region and hence will be long-lived with respect to photolysis.

show abstract

Section: Acs Earth and Space Chemistrysupporting

confidence: 52%

Section: Acs Earth and Space Chemistrymentioning

confidence: 99%

Experimental and Theoretical Studies of the Environmental Sensitivity of the Absorption Spectra and Photochemistry of Nitenpyram and Analogs

Ezell

Wang

Shemesh

et al. 2019

ACS Earth Space Chem.

View full text Add to dashboard Cite

show abstract

“…Another kinetic method described by Walash et al [152] for RAN and NIZ based on the reaction of the compounds with 7-chloro-4-nitrobenz-2-oxa-1,3diazole in borate buffer (pH 7.4) at 60 ∘ C for 25 min and the reaction product is measured at 495 nm. The protolytic constants of RAN and NIZ were studied using a spectrophotometric method [153]. (Table 3) in biological fluids by using a short polymeric chain [157], silica-based column [158], polymeric base reversedphase column [159], without solvent extraction or one-step sample preparation [158,[160][161][162], two-step extraction [163], two solvents combination for extraction [164], protein precipitation and salting out procedures [157], solid-phase extraction [165][166][167], liquid-liquid extraction with organic solvents [168][169][170], and ion-pair high-performance liquid chromatography [161,163].…”

Section: Hplc Methodsmentioning

confidence: 99%

An Overview of Analytical Determination of Diltiazem, Cimetidine, Ranitidine, and Famotidine by UV Spectrophotometry and HPLC Technique

Shafi

Siddiqui

Naseem

et al. 2013

Journal of Chemistry

View full text Add to dashboard Cite

This review article recapitulates the analytical methods for the quantitative determinations of diltiazem and three H2receptor antagonists (cimetidine, ranitidine, and famotidine) by one of the spectroscopic technique (UV spectrophotometery) and separation technique such as high-performance liquid chromatography (HPLC). The clinical and pharmaceutical analysis of these drugs requires effective analytical procedures for quality control, pharmaceutical dosage formulations, and biological fluids. An extensive survey of the literature published in various analytical and pharmaceutical chemistry-related journals has been compiled in its review. A synopsis of reported spectrophotometric and high-performance liquid chromatographic methods for individual drug is integrated. This appraisal illustrates that majority of the HPLC methods reviewed are based on the quantitative analysis of drugs in biological fluids, and they are appropriate for therapeutic drug monitoring purpose.

show abstract

“…RAN‐HCl is the product of reaction between HCl and RAN base (RAN‐B). RAN‐B, a pale‐yellow to off‐white powder, has two p K a values3 of 8.20 and 2.30, which means that it can react with more than one proton. During HCl addition, the first HCl molecule reacts with the nitrogen of the dimethylamino group, and as the pH decreases, the second HCl reacts with the ethenediamine where C‐protonation rather than N‐protonation occurs 4.…”

Section: Introductionmentioning

confidence: 99%

Improving the filterability and solid density of ranitidine hydrochloride form 1

Mirmehrabi

Rohani

Murthy

et al. 2004

Journal of Pharmaceutical Sciences

View full text Add to dashboard Cite

Protolytic constants of nizatidine, ranitidine and N,N′-dimethyl-2-nitro-1,1-ethenediamine; spectrophotometric and theoretical investigation

Cited by 30 publications

References 12 publications

Experimental and Theoretical Studies of the Environmental Sensitivity of the Absorption Spectra and Photochemistry of Nitenpyram and Analogs

Experimental and Theoretical Studies of the Environmental Sensitivity of the Absorption Spectra and Photochemistry of Nitenpyram and Analogs

An Overview of Analytical Determination of Diltiazem, Cimetidine, Ranitidine, and Famotidine by UV Spectrophotometry and HPLC Technique

Improving the filterability and solid density of ranitidine hydrochloride form 1

Contact Info

Product

Resources

About