Current Organic Chemistry - Volume 26, Issue 24, 2022

β-Nicotinamide mononucleotide (β-NMN), a key precursor in the biosynthesis of nicotinamide adenine dinucleotide (NAD+) in mammals, has significant effects in replenishing NAD+ levels in the body, so it has obvious ameliorative effects on metabolic and age-related degenerative diseases. β-NMN is widely used in healthcare products, food, and cosmetics. It has considerable commercial worth and promising medical application prospects. Hence, the development of methods for preparing β-NMN is of great research significance. This review summarized and analyzed recent developments in the chemical synthesis of β-NMN from various starting materials, which could provide helpful references for the investigation of new synthetic techniques for β-NMN and encourage its further development and large-scale application.

Melia azedarach L., a species of the mahogany family (Meliaceae), has long been used as a folk medicine for various diseases. Recent studies on this plant revealed that this plant contains many interesting bioactivities such as antioxidant, antimicrobial, antiviral, antifeedant, antidiabetic, antifungal, and cytotoxic activities. A diverse range of organic compounds has been isolated from this species, such as triterpenoids, limonoids, degraded limonoids, steroids, lignans, flavonoids, and phenolics. This review article will give a comprehensive overview of the chemical constituents and biological activity of Melia azedarach.

Breast cancer was diagnosed in around 2.3 million women in 2020. Owing to the alarming rise in the incidence of breast cancer, newer small molecules with targeted therapy are the need of the hour. A plethora of small molecules has been approved by the USFDA in the past few years. Triazine is a six-membered aromatic nitrogen heterocyclic molecule that was investigated for its various types of biological activities specially anticancer activity. Triazines are studied in many derivatives having remarkable anti-tumor activity as reported in this literature. Triazines are reported to possess a variety of biological activities and have been widely investigated as a scaffold for developing newer anti-tumor agents with an ability to inhibit various types of cancers, including breast cancers. Triazine derivatives show anticancer activity by inhibiting various targets like mTOR- kinase, PIP3-kinase, epidermal growth factor, etc. A limited number of triazine derivatives have also been clinically used for the treatment of breast cancer. A detailed study of the literature available on various derivatives of triazines with primary applicability as cytotoxic to breast cancer cell was carried out and is presented in this review. A total of 66 structurally diverse triazines have been reported in this review along with the structural features responsible for activity against various breast cancer cell lines. The primary amino residues to which the triazine based molecules bind in the estrogen receptor alpha and epidermal growth factor receptor 2, as found in various docking studies have also been detailed in the review.

Owing to the prevalent occurring in natural products and abundant bioactivities, the effective synthetic methods of fused bicyclic N,O-acetals skeletons are of great interest to chemists. This mini-review summarized the thus far synthetic progress of fused bicyclic N,O-acetals. These works were elaborated according to the different reaction types, including a) hetero-Diels-Alder cycloaddition of cyclic enamines with oxadienes; b) step-by-step reactions between cyclic enamines and electrophiles with pendant hydroxyl groups; c) [3+2] cycloaddition of indole with quinone or its equivalent and d) other novel strategies. The catalytic systems and reaction mechanisms are mainly described.

New coumarin chalcones 3j-p were conveniently obtained in high yields via Claisen-Schmidt condensation reaction, when acetyl coumarin 1 reacted with 3-aryl-1-phenyl pyrazole-4-carbaldehydes 2j-p in boiling ethanol in the presence of triethyl amine as a catalyst. Also, two synthetic pathways were afforded for the synthesis of novel tetrazolo[1,5- a]pyrimidinyl-2H-chromen-2-ones 5a-p. The first pathway is a multistep process including formation and separation of chalcones, which then were allowed to react with 5-aminotetrazole 4. While, the second pathway is a highly efficient one-pot three-component condensation reaction of 3-acetyl coumarin 1, aromatic aldehydes 2a-p and 5-aminotetrazole 4 under green and mild reaction conditions by using acetic acid (AcOH) as a catalyst and solvent. The molecular structure of products was established on the basis of their NMRs, IR and elemental analysis data. Solvent optimization was carried out in the reaction producing 3-(5-Phenyl-4,5-dihydrotetrazolo[1,5- a]pyrimidin-7-yl)-2H-chromen-2-one (5a). The advantages to using environmental-friendly acetic acid are simple operation, short reaction time, high efficient (97%), operationally facile and wide tolerance of starting materials.

Aril azides are popular reagents in the laboratory, but their explosive properties prevent their larger-scale application. The safety risk is even greater for N-heterocyclic azides, which are rarely studied. Flow chemistry can be an effective tool in the synthesis and utilization of dangerous and explosive chemicals. In small-diameter flow reactors, good heat and mass transfer prevent local hot spots and side reactions, and since only small amounts of hazardous chemicals are present at any time, the potential danger is reduced in the event of an accident. In this work, the safe syntheses of 9 different 2-azidopyridine, 2-azidopyrimidine and 2-azidoquinoxaline derivatives were successfully achieved within the continuous-flow system. In most cases, simple work-up resulted in pure products. In-line extractive work-up was also implemented, which allowed us to transform 2-azidopyridine in a subsequent Staudinger reaction in a connected flow reactor, without manual handling of the hazardous azide.