Destabilization of Glycosyl Cation by an Electron-Withdrawing Substituent at C-5 Makes Sialylation Reaction More α-Stereoselective.

Comparison of the reactivity of sialyl chlorides and bromides based on -acetylneuraminic acid (Neu5Ac) and its deaminated analogue (KDN) in reactions with MeOH and -PrOH without a promoter revealed that the acetoxy group at C-5 in a molecule of a sialic acid glycosyl donor can destabilize the corresponding glycosyl cation making the S1-like reaction pathway unfavorable. A change to the S2-like reaction pathway ensures preferential formation of the α-glycoside.

[Differential diagnosis of acute maxillary ethmoiditis complicated by orbital abscess with dacryocystitis and phlegmon of the lacrimal sac in children].

Introduction: The differential diagnosis of orbital complications of rhinosinusitis with diseases of the lacrimal sac in childhood remains unresolved both due to the similarity of the symptoms of the diseases and due to certain diagnostic difficulties requiring computed tomography.

Objective: To develop an algorithm for routing a patient to the emergency department of a multidisciplinary emergency hospital based on clinical and diagnostic distinctive features of sinusitis with orbital complications and diseases of the lacrimal sac with reactive edema of the eyelids.

Materials And Methods: A retrospective cohort analysis of children's medical histories, who were treated in the otorhinolaryngological and ophthalmological departments of the Morozovskaya Children's City Clinical Hospital during 2022 was performed for orbital complications of rhinosinusitis or dacryocystitis with reactive edema of the eyelids.

[Optimized interdisciplinary approach in the treatment of maxillary sinus upper wall fractures in children].

Unlabelled: Rehabilitation of children with fractures of the upper wall of the maxillary sinus remains relevant due to the need for a balanced approach to treatment, which would take into account both the features of traumatic injuries in children and the specifics of their age development. The article describes a technique for combined (endoscopic transnasal and transconjunctival) surgical treatment of children with fractures of the upper wall of the maxillary sinus using a sinus balloon catheter.

Objective: To study the effectiveness and safety of the functional method of treating fractures of the upper wall of the maxillary sinus using endoscopic sinus surgery and a sinus balloon catheter.

Stereocontrolled 1,2-trans-arabinofuranosylation in the absence of 2-O-acyl group in glycosyl donor.

Stereocontrolled 1,2-trans-α-arabinofuranosylation using polysilylated mono- and disaccharide glycosyl donors was investigated. A complete α-stereoselectivity of 1,2-trans-arabinofuranosylation was found for Ara-β-(1 → 2)-Ara disaccharide glycosyl donors containing five triisopropylsilyl (TIPS) groups with arylthiol (1) (as shown in our previous publications) or N-phenyltrifluoroacetimidoyl (2) (this work) leaving groups. Conversely, in case of monosaccharide thioglycosides polysilylated with acyclic silyl groups (TIPS, TBDPS), stereoselectivity of glycosylation was lower (α:β = 7-8:1), although the desired α-isomer still dominated.

Mild and General Protocol for Selective Deacetylation of Acetyl/Benzoyl-Protected Carbohydrates.

Herein, we report a mild and general protocol for chemoselective deacetylation of mixed acetyl- and benzoyl-protected carbohydrates under mild acidic conditions. The protocol allows quick access to partially protected carbohydrates, which serve as versatile synthetic intermediates during the total synthesis of various mono- and oligosaccharide targets. The applicability of the developed protocol was successfully demonstrated on a range of carbohydrate substrates of various configurations and substitution patterns featuring functionalized aliphatic and aromatic aglycones.