Facile synthesis of high specific activity 4‐[1‐14C]butyl‐1,2‐diphenylpyrazolidine‐3,5‐dione (phenylbutazone) using nucleophilic substitution

Metabolism, environmental fate, and low concentration food residue studies would be facilitated by the use of radiolabeled test articles that can be readily quantified within complex matrices. However, radiochemical approaches for such studies require high specific activities to allow analytical detection of correspondingly low masses of test article. The synthesis of high specific activity (>50 μCi/μmol) [¹⁴C]‐radiolabeled phenylbutazone presents a challenge using existing methodology, mainly due to the low solvent volumes required and vigorous refluxing needed to close the pyrazolidinedione ring. Herein, we report on the significant modification of an existing method that allows the synthesis of low masses of high specific activity (>50 μCi/μmol) [¹⁴C]‐phenylbutazone under mild conditions with simple purification and high yield. The closure of the pyrazolidinedione ring of 1,2‐diphenyl‐3,5‐pyrazolidinedione was accomplished as a first step with unlabeled 1,2‐diphenylhydrazine and diethyl malonate in 32% yield under gram‐scale conditions, which avoided the challenges of low solvent use and vigorous refluxing. Low mass of high specific activity n‐[1‐¹⁴C]‐butyl bromide was then added via a nucleophilic substitution reaction as a final step. Yields ranged from 65% to 92% during multiple synthetic attempts with unlabeled butyl bromide and were greatly influenced by reaction stoichiometry and the selection of base.     

Arrowhead elastic for simultaneous correction of overjet and overbite

Arrowhead elastic may be integrated with fixed appliances to achieve rapid correction of increased overjet and overbite during comprehensive orthodontic treatment. This technique is applicable in routine class II cases involving deep bite, during retention phase in growing children treated with twin block and postsurgically in adult hypodivergent cases.     

Epilepsy and dental procedures. A review

This paper is a review of the dental management of patients with epilepsy. It includes discussion of the effects anti-epileptic drugs have on dental procedures and addresses complications and side effects of these drugs. A clinical case photo is presented to show gingival hyperplasia, along with four tables on which common antiepileptic medications are enumerated.     

Intra-coronal bleaching in young permanent and primary tooth with biologic perspectives

The odd attracts society in odd manner, as is the case when a patient with discolored tooth smiles. Because of that, pediatric patients have psychological impact. Trauma and pulpal necrosis are the most common causes for discoloration of teeth. If tooth is intact, intra-coronal bleaching is the most conservative and noninvasive treatment modality provided, it is done cautiously. This article intends to present two case-reports of successful intra-coronal bleaching using milder (sodium perborate) and tissue-friendly bleaching agent with walking bleach.