定义Definition
哈沃斯投影式把环状单糖画成垂直于纸面的平面五元或六元环，取代基画在环的上方或下方，用来表示呋喃糖、吡喃糖的立体构型。
A Haworth projection draws a cyclic sugar as a flat five- or six-membered ring perpendicular to the page, with substituents above or below the ring, showing the configuration of furanoses and pyranoses.
画法Conventions
环氧原子在后右方（吡喃糖），端基碳 C-1 在右。由费歇尔式转换：费歇尔式中在右边的 –OH 在哈沃斯式中朝下，在左边的朝上；D 型糖的 C-5 上 –CH₂OH 朝上。端基 –OH 朝下为 α，朝上为 β（D 型糖）。
For pyranoses the ring oxygen is at the back right with C-1 at the right. From a Fischer projection, right-hand –OH groups point down and left-hand ones up; for D-sugars the C-5 CH₂OH points up. Anomeric OH down is α, up is β (D-sugars).
由来Origin
英国化学家沃尔特·哈沃斯于 1920 年代提出，他确定了糖的环状结构并首次合成维生素 C，获 1937 年诺贝尔化学奖。
Introduced in the 1920s by Walter Haworth, who established cyclic sugar structures and first synthesised vitamin C, earning the 1937 Nobel Prize.
局限Limitation
六元环实际是椅式而非平面，哈沃斯式不能表示直立键与平伏键，需要构象分析时改用椅式。
Six-membered rings are really chairs, so Haworth drawings hide axial/equatorial positions; use chair drawings for conformational analysis.
年表Timeline
- 1926
哈沃斯提出吡喃糖环结构
Haworth proposes the pyranose ring structure
- 1937
哈沃斯获诺贝尔化学奖
Haworth receives the Nobel Prize