This total synthesis effort was motivated primarily by the desire to generate new chemical understanding, rather than with an expectation of the practical commercial production of paclitaxel. The first laboratories to complete the total synthesis from much less complex starting materials were the research groups of Robert A. Holton, who had the first article to be accepted for publication, and of K. C. Nicolaou who had the first article to appear in print (by a week, on 7 February 1994). Though the Holton submission preceded the Nicolaou by a month (21 December 1993 versus 24 January 1994), the near coincidence of the publications arising from each of these massive, multiyear efforts—11–18 authors appearing on each of the February 1994 publications—has led the ending of the race to be termed a "tie" or a "photo finish", though each group has argued that their synthetic strategy and tactics were superior.As of 2006, five additional research groups had reported successful total syntheses of paclitaxel: Wender et al. in 1997, and Kuwajima et al. and Mukaiyama et al. in 1998 with further linear syntheses, and Danishefsky et al. in 1996 and  Takahashi et al. in 2006 with further convergent syntheses.
Esophageal diseases can derive from congenital conditions, or they can be acquired later in life. Many people experience a burning sensation in their chest occasionally, caused by stomach acids refluxing into the esophagus, normally called heartburn. Extended exposure to heartburn may erode the lining of the esophagus, leading potentially to Barretts esophagus which is associated with an increased risk of adenocarcinoma most commonly found in the distal one-third of the esophagus. Some people also experience a sensation known as globus esophagus, where it feels as if a ball is lodged in the lower part of the esophagus. The following are additional diseases and conditions that affect the esophagus:

Achalasia
Acute esophageal necrosis
Barretts esophagus
Boerhaave syndrome
Caustic injury to the esophagus
Chagas disease
Diffuse esophageal spasm
Esophageal atresia and tracheoesophageal fistula
Esophageal cancer
Esophageal dysphagia
Esophageal varices
Esophageal web
Esophagitis
GERD
Hiatus hernia
Jackhammer esophagus (hypercontractile peristalsis)
Killian–Jamieson diverticulum
Mallory–Weiss syndrome
Neurogenic dysphagia
Nutcracker esophagus
Schatzkis ring
Zenkers diverticulum

References
External links

Esophageal and Swallowing Disorders, Merck & Company Inc.