Methods for direct conversion of primary nitroalkanes to nitriles

: In recent years, reductive dehydration of primary nitro compounds has been demonstrated as an attractive and alternative approach for the direct synthesis of nitriles. Although scattered information on the conversion of alkyl nitrites and/or nitroalkanes to the corresponding nitriles has been reported in the literature, a research paper describing comprehensive information at one place is scarce. The present review has attempted to focus on the uncatalyzed as well as catalyzed reductive dehydration of nitro compounds directly into nitriles in the presence of dehydrating reagents. Non-metal and metal-catalyzed dehydration of nitro compounds and the use of radical chemistry in accessing nitriles have been highlighted in this review article.

Illékony nitritszármazékok („popperek”) által okozott methaemoglobinaemia

Összefoglaló. A methaemoglobinaemia az oxigén szállítására képtelen methemoglobin szintjének kóros emelkedését jelenti a vérben, ami jelentős szöveti oxigénhiányt okozhat, súlyos, akár életveszélyes tünetekhez vezethet. Methaemoglobinaemiát számos, oxidáló hatású exogén anyag idézhet elő, ezek közé tartoznak a partidrogként használt alkil-nitritek, az ún. „popperek” is. A „poppereket” korábban „alacsony rizikójú” drogként tartották számon, azonban számos esetet közöltek, amikor súlyos, időnként fatális kimenetelű methaemoglobinaemiát okoztak. A folyadékok gőzének belélegzése euforizáló, szexuálisvágy-fokozó és simaizom-lazító hatású, ezért a „popperek” igen népszerűek a homo- és biszexuális férfiak körében, de fiatal felnőttek és tinédzserek is használják. A folyadékok szájon át való fogyasztása különösen veszélyes. A szerzők két esetet ismertetnek, amelyekben a „popperek” használatát követően methaemoglobinaemia alakult ki. Mindkét betegnél, a jó általános állapot mellett, centrális és perifériás cyanosis tüneteit észlelték. Az alkalmazás módja (inhaláció/lenyelés), a methaemoglobinaemia súlyossága (16,4% és 57%) és a terápia eltérő volt a két betegnél. Az első beteg oxigén adása és tüneti kezelés mellett gyógyult, a másodiknál antidotum (metilénkék) adására is szükség volt. Mindketten panaszmentesen távoztak a kórházból. A szerzők célja az volt, hogy felhívják a figyelmet az illékony alkil-nitrit-származékok által okozott methaemoglobinaemiára, annak felismerésére, kezelésére, és bemutassák azok kevésbé ismert szövődményeit is. Orv Hetil. 2021; 162(8): 306–313. Summary. Methemoglobinemia means the abnormally elevated level of methemoglobin in the blood, which is incapable of oxygen transport, accordingly it can cause significant tissue hypoxia, leading to severe or even life-threatening clinical symptoms. Several exogen oxidative agents can induce methemoglobinemia, including alkyl-nitrites which are also used as party drugs, the so-called ‘poppers’. The ‘poppers’ were previously considered ‘low-risk’ drugs, however, several cases have been published when they caused severe, sometimes fatal methemoglobinemia. Inhaling vapours from liquids has euphoric, smooth-muscle relaxing and aphrodisiac effects, therefore ‘poppers’ are extremely popular among gay and bisexual men but also used by young adults and teenagers. Oral consumption of the fluids is particularly dangerous. The authors present two cases when methemoglobinemia developed after ‘poppers’ usage. Both patients were in good general condition and symptoms of central and peripheral cyanosis were detected. The method of application (inhalation/ ingestion), the severity of methemoglobinemia (16,4% and 57%) and the treatment were different in the two patients. The first patient recovered with inhalation of oxygen and symptomatic treatment; the second patient required administration of antidote (methylene blue). Both patients left the hospital without complaints. The authors’ aim was to attract attention to methemoglobinemia caused by volatile alkyl-nitrites, its recognition, treatment and to present their lesser-known complications. Orv Hetil. 2021; 12(8): 306–313.

HIV incidence among men who have sex with men and transgender women in four provinces in Thailand

The HIV epidemic in Thailand is concentrated in key populations, with the highest rates in men who have sex with men (MSM) and transgender women (TG). Previous studies of HIV incidence in these groups have been limited mostly to Bangkok. We measured HIV incidence in MSM and TG in four provinces and evaluated factors associated with incident infections to inform public health prevention efforts. An analysis was conducted using data collected during a prospective observational cohort study during April 2015–May 2018 in outpatient clinics in five hospitals across four provinces in Thailand. MSM and TG aged ≥18 years, who were not known to be HIV-infected, and who reported anal intercourse with a male or TG without a condom in the past six months were enrolled. Participants were followed-up every 6 months for 18 months with questionnaires and HIV testing. A total of 40 HIV seroconversions occurred during follow-up, resulting in an HIV incidence of 3.5 per 100 person-years (95% CI 2.5, 4.8). Multivariate analyses indicated that identifying as gay (adjusted hazard ratio [AHR] 4.9; 95% CI 1.7–14.2), having receptive anal sex in the past six months (AHR 3.6; 95% CI 1.4–9.5), using alcohol (AHR 3.3; 95% CI 1.3–8.3), and taking alkyl nitrites (AHR 4.4; 95% CI 1.7–11.2) in the past six months were all independently associated with HIV infection. Overall this study found a lower HIV incidence in the highest risk population in Thailand compared with similar studies in Bangkok. Accelerated prevention efforts are needed to make the goal of ‘zero new infections’ possible in Thailand.

The Untimely Popping Phial: Poppers as an Unusual Cause of Skin Corrosion of the Thigh

Background. Alkyl nitrites or “poppers” are widely used as sex-drugs due to their aphrodisiac and muscle relaxant effects. We describe the rare case of a large-sized dermatitis after direct skin contact with the poppers-fluid in a poppers user. Case Presentation. A 52-year-old patient presented to the emergency department due to burning pain on his proximal right thigh and scrotum. Clinical examination showed an 8 × 5 cm measuring burning wound resembling lesion. During further history the patient mentioned that the day before presentation a “poppers” phial unintentionally opened in his pocket and the fluid leaked. Conclusions. The present case shows severe skin defects after skin-contact with alkyl nitrates in a “poppers” user. Maculopathy and methemoglobinemia are prominent unwanted side effects of “poppers” use. However, our report demonstrates that attention should also be paid to potential harm for the skin.

EFFECTS OF VOLATILE ORGANIC ALKILNYTRITIS COMPOUNDS ON THE ORGANISM AND THE POSSIBILITY OF THEIR FORENSIC CHEMICAL DETECTING

The article reviews and summarizes theoretical issues related to the abuse of inhalants, provides data on the pharmacological and toxic effects, the legal status of the substances under study, the chemical analysis of alkyl nitrites. The risk to human health is associated with the ability of alkyl nitrites to cause methemoglobin, changes in organs and systems, including myocardial dystrophy, chronic inflammation of the upper respiratory tract. The use of isopropyl nitrite can cause damage to the retina, maculapathy. ”Poppers” is a subgroup of volatile substances – alkyl nitrites, represented by compounds or mixtures and contain more than one alkyl nitrite, mainly: butyl nitrite, isobutyl nitrite or amyl nitrite, isopentyl nitrite, or 2-methyl butyl nitrite. On the Internet market they are presented under the following slang names: amyls, hardware, liquid gold, locker room, rock hard, rush, snapper, TNT . Chemico-toxicological analysis is carried out by chromatography methods – the vapor phase analysis with identification on a flame-ionization or mass-selective detector is used. Blood, in cases of deadly intoxication, lung tissue are the best objects. One of the signs of using alkyl nitrites is the formation of methemoglobin, the definition of which has an important diagnostic value. Joint detection of metabolites of alkyl nitrites and methemoglobin may indicate the possible use of alkyl nitrites. The legal status of alkyl nitrites in most countries varies from free use to medical prescription sales. In the Republic of Kazakhstan, alkyl nitrites are not under the control of the law “On Narcotic Drugs, Psychotropic Substances, Their Analogues and Precursors, and Measures to Counteract Their Illicit Circulation and Abuse”. Their abuse is a concern because of their detrimental health effects. Key words: alkyl nitrite, toxicomania, poppers, methemoglobinemia, maculopathy, forensic expertise, research, chemical analysis.

HO_<i>x</i> and NO_<i>x</i> production in oxidation flow reactors via photolysis of isopropyl nitrite, isopropyl nitrite-d₇, and 1,3-propyl dinitrite at <i>λ</i> = 254, 350, and 369 nm

Oxidation flow reactors (OFRs) are an emerging technique for studying the formation and oxidative aging of organic aerosols and other applications. In these flow reactors, hydroxyl radicals (OH), hydroperoxyl radicals (HO2), and nitric oxide (NO) are typically produced in the following ways: photolysis of ozone (O3) at λ=254 nm, photolysis of H2O at λ=185 nm, and via reactions of O(1D) with H2O and nitrous oxide (N2O); O(1D) is formed via photolysis of O3 at λ=254 nm and/or N2O at λ=185 nm. Here, we adapt a complementary method that uses alkyl nitrite photolysis as a source of OH via its production of HO2 and NO followed by the reaction NO + HO2 → NO2 + OH. We present experimental and model characterization of the OH exposure and NOx levels generated via photolysis of C3 alkyl nitrites (isopropyl nitrite, perdeuterated isopropyl nitrite, 1,3-propyl dinitrite) in the Potential Aerosol Mass (PAM) OFR as a function of photolysis wavelength (λ=254 to 369 nm) and organic nitrite concentration (0.5 to 20 ppm). We also apply this technique in conjunction with chemical ionization mass spectrometer measurements of multifunctional oxidation products generated following the exposure of α-Pinene to HOx and NOx obtained using both isopropyl nitrite and O3 + H2O + N2O as the radical precursors.

HO_x and NO_x production in oxidation flow reactors via photolysis of isopropyl nitrite, isopropyl nitrite-d₇, and 1,3-propyl dinitrite at λ = 254, 350, and 369 nm

Oxidation flow reactors (OFRs) are an emerging technique for studying the formation and oxidative aging of organic aerosols and other applications. In these flow reactors, hydroxyl radicals (OH), hydroperoxyl radicals (HO2), and nitric oxide (NO) are typically produced in the following ways: photolysis of ozone (O3) at λ = 254 nm, photolysis of H2O at λ = 185 nm, and via reactions of O(1D) with H2O and nitrous oxide (N2O); O(1D) is formed via photolysis of O3 at λ = 254 nm and/or N2O at λ = 185 nm. Here, we adapt a complementary method that uses alkyl nitrite photolysis as a source of OH via its production of HO2 and NO followed by the reaction NO + HO2 → NO2 + OH. We present experimental and model characterization of the OH exposure and NOx levels generated via photolysis of C3 alkyl nitrites (isopropyl nitrite, perdeuterated isopropyl nitrite, 1,3-propyl dinitrite) in the Potential Aerosol Mass (PAM) OFR as a function of photolysis wavelength (λ = 254 to 369 nm) and organic nitrite concentration (0.5 to 20 ppm). We also apply this technique in conjunction with chemical ionization mass spectrometer measurements of multifunctional oxidation products generated following the exposure of α-pinene to HOx and NOx obtained using both isopropyl nitrite and O3 + H2O + N2O as the radical precursors.

An Efficient Cyanide-Free Approach towards 1-(2-Pyridyl)isoquinoline-3-carbonitriles via the Reaction of 5-Phenacyl-1,2,4-triazines with 1,2-Dehydrobenzene in the Presence of Alkyl Nitrites

A cyanide-free method for the preparation of 1-(2-pyridyl)isoquinoline-3-carbonitriles (3-cyanoisoquinolines) was developed. The interaction of 5-phenacyl-3-(2-pyridyl)-1,2,4-triazines with 1,2-dehydrobenzene generated in situ from anthranilic acid and an excess of amyl nitrites afforded the target compounds in good yields. The proposed mechanism involves the in situ transformation of the 5-phenacyl group into the 5-cyano group under the action of alkyl nitrite and the following inverse demand aza-Diels–Alder reaction of thus formed 5-cyano-1,2,4-triazines with 1,2-dehydrobenzene affording the target products. The presence of the 5-phenacyl substituent is a key for the reaction, as in case of 5-styryl- or 5-phenylethynyl-3-(2-pyridyl)-1,2,4-triazines the formation of the 1,2,4-triazine ring-transformation products was observed